diff --git a/client/crashpad_info.cc b/client/crashpad_info.cc
index 5913be81..36471a10 100644
--- a/client/crashpad_info.cc
+++ b/client/crashpad_info.cc
@@ -101,7 +101,8 @@ CrashpadInfo::CrashpadInfo()
       gather_indirectly_referenced_memory_(TriState::kUnset),
       padding_0_(0),
       extra_memory_ranges_(nullptr),
-      simple_annotations_(nullptr)
+      simple_annotations_(nullptr),
+      user_data_minidump_stream_head_(nullptr)
 #if !defined(NDEBUG) && defined(OS_WIN)
       ,
       invalid_read_detection_(0xbadc0de)
@@ -109,4 +110,17 @@ CrashpadInfo::CrashpadInfo()
 {
 }
 
+void CrashpadInfo::AddUserDataMinidumpStream(uint32_t stream_type,
+                                             const void* data,
+                                             size_t size) {
+  auto to_be_added = new internal::UserDataMinidumpStreamListEntry();
+  to_be_added->next = base::checked_cast<uint64_t>(
+      reinterpret_cast<uintptr_t>(user_data_minidump_stream_head_));
+  to_be_added->stream_type = stream_type;
+  to_be_added->base_address =
+      base::checked_cast<uint64_t>(reinterpret_cast<uintptr_t>(data));
+  to_be_added->size = base::checked_cast<uint64_t>(size);
+  user_data_minidump_stream_head_ = to_be_added;
+}
+
 }  // namespace crashpad
diff --git a/client/crashpad_info.h b/client/crashpad_info.h
index 4dd61abe..a181f997 100644
--- a/client/crashpad_info.h
+++ b/client/crashpad_info.h
@@ -29,6 +29,29 @@
 
 namespace crashpad {
 
+namespace internal {
+
+//! \brief A linked list of blocks representing custom streams in the minidump,
+//!     with addresses (and size) stored as uint64_t to simplify reading from
+//!     the handler process.
+struct UserDataMinidumpStreamListEntry {
+  //! \brief The address of the next entry in the linked list.
+  uint64_t next;
+
+  //! \brief The base address of the memory block in the target process' address
+  //!     space that represents the user data stream.
+  uint64_t base_address;
+
+  //! \brief The size of memory block in the target process' address space that
+  //!     represents the user data stream.
+  uint64_t size;
+
+  //! \brief The stream type identifier.
+  uint32_t stream_type;
+};
+
+}  // namespace internal
+
 //! \brief A structure that can be used by a Crashpad-enabled program to
 //!     provide information to the Crashpad crash handler.
 //!
@@ -89,7 +112,7 @@ struct CrashpadInfo {
   //! that it has been disabled.
   //!
   //! The Crashpad handler should not normally be disabled. More commonly, it
-  //! is appropraite to disable crash report upload by calling
+  //! is appropriate to disable crash report upload by calling
   //! Settings::SetUploadsEnabled().
   void set_crashpad_handler_behavior(TriState crashpad_handler_behavior) {
     crashpad_handler_behavior_ = crashpad_handler_behavior;
@@ -130,6 +153,27 @@ struct CrashpadInfo {
     gather_indirectly_referenced_memory_ = gather_indirectly_referenced_memory;
   }
 
+  //! \brief Adds a custom stream to the minidump.
+  //!
+  //! The memory block referenced by \a data and \a size will added to the
+  //! minidump as separate stream with type \stream_type. The memory referred to
+  //! by \a data and \a size is owned by the caller and must remain valid while
+  //! it is in effect for the CrashpadInfo object.
+  //!
+  //! Note that streams will appear in the minidump in the reverse order to
+  //! which they are added.
+  //!
+  //! TODO(scottmg) This is currently only supported on Windows.
+  //!
+  //! \param[in] stream_type The stream type identifier to use. This should be
+  //!     normally be larger than `MINIDUMP_STREAM_TYPE::LastReservedStream`
+  //!     which is `0xffff`.
+  //! \param[in] data The base pointer of the stream data.
+  //! \param[in] size The size of the stream data.
+  void AddUserDataMinidumpStream(uint32_t stream_type,
+                                 const void* data,
+                                 size_t size);
+
   enum : uint32_t {
     kSignature = 'CPad',
   };
@@ -154,6 +198,7 @@ struct CrashpadInfo {
   uint8_t padding_0_;
   SimpleAddressRangeBag* extra_memory_ranges_;  // weak
   SimpleStringDictionary* simple_annotations_;  // weak
+  internal::UserDataMinidumpStreamListEntry* user_data_minidump_stream_head_;
 
 #if !defined(NDEBUG) && defined(OS_WIN)
   uint32_t invalid_read_detection_;
diff --git a/compat/non_win/dbghelp.h b/compat/non_win/dbghelp.h
index 2b7c974c..71ef1f4c 100644
--- a/compat/non_win/dbghelp.h
+++ b/compat/non_win/dbghelp.h
@@ -176,6 +176,10 @@ enum MINIDUMP_STREAM_TYPE {
 
   //! \brief The stream type for MINIDUMP_MEMORY_INFO_LIST.
   MemoryInfoListStream = 16,
+
+  //! \brief Values greater than this value will not be used by the system
+  //!     and can be used for custom user data streams.
+  LastReservedStream = 0xffff,
 };
 
 //! \brief Information about the CPU (or CPUs) that ran the process that the
diff --git a/handler/win/crashy_test_program.cc b/handler/win/crashy_test_program.cc
index a3331398..a2b74134 100644
--- a/handler/win/crashy_test_program.cc
+++ b/handler/win/crashy_test_program.cc
@@ -225,6 +225,18 @@ int CrashyMain(int argc, wchar_t* argv[]) {
   crashpad::CrashpadInfo::GetCrashpadInfo()
       ->set_gather_indirectly_referenced_memory(TriState::kEnabled);
 
+  std::vector<uint8_t> data_stream1(128, 'x');
+  crashpad::CrashpadInfo::GetCrashpadInfo()->AddUserDataMinidumpStream(
+      222222,
+      reinterpret_cast<const void*>(data_stream1.data()),
+      data_stream1.size());
+
+  std::vector<uint8_t> data_stream2(4096, 'z');
+  crashpad::CrashpadInfo::GetCrashpadInfo()->AddUserDataMinidumpStream(
+      333333,
+      reinterpret_cast<const void*>(data_stream2.data()),
+      data_stream2.size());
+
   AllocateMemoryOfVariousProtections();
 
   if (InitializeCriticalSectionWithDebugInfoIfPossible(
diff --git a/minidump/minidump.gyp b/minidump/minidump.gyp
index 3f714668..35528060 100644
--- a/minidump/minidump.gyp
+++ b/minidump/minidump.gyp
@@ -72,6 +72,8 @@
         'minidump_thread_writer.h',
         'minidump_unloaded_module_writer.cc',
         'minidump_unloaded_module_writer.h',
+        'minidump_user_stream_writer.cc',
+        'minidump_user_stream_writer.h',
         'minidump_writable.cc',
         'minidump_writable.h',
         'minidump_writer_util.cc',
diff --git a/minidump/minidump_file_writer.cc b/minidump/minidump_file_writer.cc
index 0c79c78d..7f8f47d5 100644
--- a/minidump/minidump_file_writer.cc
+++ b/minidump/minidump_file_writer.cc
@@ -28,8 +28,10 @@
 #include "minidump/minidump_thread_id_map.h"
 #include "minidump/minidump_thread_writer.h"
 #include "minidump/minidump_unloaded_module_writer.h"
+#include "minidump/minidump_user_stream_writer.h"
 #include "minidump/minidump_writer_util.h"
 #include "snapshot/exception_snapshot.h"
+#include "snapshot/module_snapshot.h"
 #include "snapshot/process_snapshot.h"
 #include "util/file/file_writer.h"
 #include "util/numeric/safe_assignment.h"
@@ -96,6 +98,14 @@ void MinidumpFileWriter::InitializeFromSnapshot(
   module_list->InitializeFromSnapshot(process_snapshot->Modules());
   AddStream(std::move(module_list));
 
+  for (const auto& module : process_snapshot->Modules()) {
+    for (const UserMinidumpStream* stream : module->CustomMinidumpStreams()) {
+      auto user_stream = make_scoped_ptr(new MinidumpUserStreamWriter());
+      user_stream->InitializeFromSnapshot(stream);
+      AddStream(std::move(user_stream));
+    }
+  }
+
   auto unloaded_modules = process_snapshot->UnloadedModules();
   if (!unloaded_modules.empty()) {
     auto unloaded_module_list =
diff --git a/minidump/minidump_test.gyp b/minidump/minidump_test.gyp
index 30a179f1..cdae4caa 100644
--- a/minidump/minidump_test.gyp
+++ b/minidump/minidump_test.gyp
@@ -50,6 +50,7 @@
         'minidump_thread_id_map_test.cc',
         'minidump_thread_writer_test.cc',
         'minidump_unloaded_module_writer_test.cc',
+        'minidump_user_stream_writer_test.cc',
         'minidump_writable_test.cc',
         'test/minidump_context_test_util.cc',
         'test/minidump_context_test_util.h',
diff --git a/minidump/minidump_user_stream_writer.cc b/minidump/minidump_user_stream_writer.cc
new file mode 100644
index 00000000..7332cd01
--- /dev/null
+++ b/minidump/minidump_user_stream_writer.cc
@@ -0,0 +1,73 @@
+// Copyright 2016 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "minidump/minidump_user_stream_writer.h"
+
+#include "util/file/file_writer.h"
+
+namespace crashpad {
+
+MinidumpUserStreamWriter::MinidumpUserStreamWriter()
+    : stream_type_(0), reader_() {
+}
+
+MinidumpUserStreamWriter::~MinidumpUserStreamWriter() {
+}
+
+void MinidumpUserStreamWriter::InitializeFromSnapshot(
+    const UserMinidumpStream* stream) {
+  DCHECK_EQ(state(), kStateMutable);
+
+  stream_type_ = stream->stream_type();
+  if (stream->memory())
+    stream->memory()->Read(&reader_);
+}
+
+bool MinidumpUserStreamWriter::Freeze() {
+  DCHECK_EQ(state(), kStateMutable);
+  DCHECK_NE(stream_type_, 0u);
+  return MinidumpStreamWriter::Freeze();
+}
+
+size_t MinidumpUserStreamWriter::SizeOfObject() {
+  DCHECK_GE(state(), kStateFrozen);
+  return reader_.size();
+}
+
+std::vector<internal::MinidumpWritable*>
+MinidumpUserStreamWriter::Children() {
+  DCHECK_GE(state(), kStateFrozen);
+  return std::vector<internal::MinidumpWritable*>();
+}
+
+bool MinidumpUserStreamWriter::WriteObject(FileWriterInterface* file_writer) {
+  DCHECK_EQ(state(), kStateWritable);
+  return file_writer->Write(reader_.data(), reader_.size());
+}
+
+MinidumpStreamType MinidumpUserStreamWriter::StreamType() const {
+  return static_cast<MinidumpStreamType>(stream_type_);
+}
+
+MinidumpUserStreamWriter::MemoryReader::~MemoryReader() {}
+
+bool MinidumpUserStreamWriter::MemoryReader::MemorySnapshotDelegateRead(
+    void* data,
+    size_t size) {
+  data_.resize(size);
+  memcpy(&data_[0], data, size);
+  return true;
+}
+
+}  // namespace crashpad
diff --git a/minidump/minidump_user_stream_writer.h b/minidump/minidump_user_stream_writer.h
new file mode 100644
index 00000000..b31247a3
--- /dev/null
+++ b/minidump/minidump_user_stream_writer.h
@@ -0,0 +1,77 @@
+// Copyright 2016 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef CRASHPAD_MINIDUMP_MINIDUMP_USER_STREAM_WRITER_H_
+#define CRASHPAD_MINIDUMP_MINIDUMP_USER_STREAM_WRITER_H_
+
+#include <windows.h>
+#include <dbghelp.h>
+#include <stdint.h>
+
+#include <vector>
+
+#include "base/macros.h"
+#include "minidump/minidump_stream_writer.h"
+#include "minidump/minidump_writable.h"
+#include "snapshot/module_snapshot.h"
+
+namespace crashpad {
+
+//! \brief The writer for a MINIDUMP_USER_STREAM in a minidump file.
+class MinidumpUserStreamWriter final : public internal::MinidumpStreamWriter {
+ public:
+  MinidumpUserStreamWriter();
+  ~MinidumpUserStreamWriter() override;
+
+  //! \brief Initializes a MINIDUMP_USER_STREAM based on \a stream.
+  //!
+  //! \param[in] stream The memory and stream type to use as source data.
+  //!
+  //! \note Valid in #kStateMutable.
+  void InitializeFromSnapshot(const UserMinidumpStream* stream);
+
+ protected:
+  // MinidumpWritable:
+  bool Freeze() override;
+  size_t SizeOfObject() override;
+  std::vector<internal::MinidumpWritable*> Children() override;
+  bool WriteObject(FileWriterInterface* file_writer) override;
+
+  // MinidumpStreamWriter:
+  MinidumpStreamType StreamType() const override;
+
+ private:
+  class MemoryReader : public MemorySnapshot::Delegate {
+   public:
+    ~MemoryReader() override;
+    bool MemorySnapshotDelegateRead(void* data, size_t size) override;
+
+    const void* data() const {
+      return reinterpret_cast<const void*>(data_.data());
+    }
+    size_t size() const { return data_.size(); }
+
+   private:
+    std::vector<uint8_t> data_;
+  };
+
+  uint32_t stream_type_;
+  MemoryReader reader_;
+
+  DISALLOW_COPY_AND_ASSIGN(MinidumpUserStreamWriter);
+};
+
+}  // namespace crashpad
+
+#endif  // CRASHPAD_MINIDUMP_MINIDUMP_USER_STREAM_WRITER_H_
diff --git a/minidump/minidump_user_stream_writer_test.cc b/minidump/minidump_user_stream_writer_test.cc
new file mode 100644
index 00000000..ae58d825
--- /dev/null
+++ b/minidump/minidump_user_stream_writer_test.cc
@@ -0,0 +1,104 @@
+// Copyright 2016 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "minidump/minidump_user_stream_writer.h"
+
+#include <string>
+#include <utility>
+
+#include "gtest/gtest.h"
+#include "minidump/minidump_file_writer.h"
+#include "minidump/test/minidump_file_writer_test_util.h"
+#include "minidump/test/minidump_writable_test_util.h"
+#include "snapshot/test/test_memory_snapshot.h"
+#include "util/file/string_file.h"
+
+namespace crashpad {
+namespace test {
+namespace {
+
+// The user stream is expected to be the only stream.
+void GetUserStream(const std::string& file_contents,
+                   MINIDUMP_LOCATION_DESCRIPTOR* user_stream_location,
+                   uint32_t stream_type) {
+  const size_t kDirectoryOffset = sizeof(MINIDUMP_HEADER);
+  const size_t kUserStreamOffset =
+      kDirectoryOffset + sizeof(MINIDUMP_DIRECTORY);
+
+  const MINIDUMP_DIRECTORY* directory;
+  const MINIDUMP_HEADER* header =
+      MinidumpHeaderAtStart(file_contents, &directory);
+  ASSERT_NO_FATAL_FAILURE(VerifyMinidumpHeader(header, 1, 0));
+  ASSERT_TRUE(directory);
+
+  const size_t kDirectoryIndex = 0;
+
+  ASSERT_EQ(stream_type, directory[kDirectoryIndex].StreamType);
+  EXPECT_EQ(kUserStreamOffset, directory[kDirectoryIndex].Location.Rva);
+  *user_stream_location = directory[kDirectoryIndex].Location;
+}
+
+TEST(MinidumpUserStreamWriter, NoData) {
+  MinidumpFileWriter minidump_file_writer;
+  auto user_stream_writer = make_scoped_ptr(new MinidumpUserStreamWriter());
+  const uint32_t kTestStreamId = 0x123456;
+  auto stream = make_scoped_ptr(new UserMinidumpStream(kTestStreamId, nullptr));
+  user_stream_writer->InitializeFromSnapshot(stream.get());
+  minidump_file_writer.AddStream(std::move(user_stream_writer));
+
+  StringFile string_file;
+  ASSERT_TRUE(minidump_file_writer.WriteEverything(&string_file));
+
+  ASSERT_EQ(sizeof(MINIDUMP_HEADER) + sizeof(MINIDUMP_DIRECTORY),
+            string_file.string().size());
+
+  MINIDUMP_LOCATION_DESCRIPTOR user_stream_location;
+  ASSERT_NO_FATAL_FAILURE(GetUserStream(
+      string_file.string(), &user_stream_location, kTestStreamId));
+  EXPECT_EQ(0u, user_stream_location.DataSize);
+}
+
+TEST(MinidumpUserStreamWriter, OneStream) {
+  MinidumpFileWriter minidump_file_writer;
+  auto user_stream_writer = make_scoped_ptr(new MinidumpUserStreamWriter());
+  const uint32_t kTestStreamId = 0x123456;
+
+  TestMemorySnapshot* test_data = new TestMemorySnapshot();
+  test_data->SetAddress(97865);
+  const size_t kStreamSize = 128;
+  test_data->SetSize(kStreamSize);
+  test_data->SetValue('c');
+  auto stream =
+      make_scoped_ptr(new UserMinidumpStream(kTestStreamId, test_data));
+  user_stream_writer->InitializeFromSnapshot(stream.get());
+  minidump_file_writer.AddStream(std::move(user_stream_writer));
+
+  StringFile string_file;
+  ASSERT_TRUE(minidump_file_writer.WriteEverything(&string_file));
+
+  ASSERT_EQ(sizeof(MINIDUMP_HEADER) + sizeof(MINIDUMP_DIRECTORY) + kStreamSize,
+            string_file.string().size());
+
+  MINIDUMP_LOCATION_DESCRIPTOR user_stream_location;
+  ASSERT_NO_FATAL_FAILURE(GetUserStream(
+      string_file.string(), &user_stream_location, kTestStreamId));
+  EXPECT_EQ(kStreamSize, user_stream_location.DataSize);
+  const std::string stream_data = string_file.string().substr(
+      user_stream_location.Rva, user_stream_location.DataSize);
+  EXPECT_EQ(std::string(kStreamSize, 'c'), stream_data);
+}
+
+}  // namespace
+}  // namespace test
+}  // namespace crashpad
diff --git a/snapshot/mac/module_snapshot_mac.cc b/snapshot/mac/module_snapshot_mac.cc
index 4f4df2a5..4eaa12b1 100644
--- a/snapshot/mac/module_snapshot_mac.cc
+++ b/snapshot/mac/module_snapshot_mac.cc
@@ -187,5 +187,10 @@ std::set<CheckedRange<uint64_t>> ModuleSnapshotMac::ExtraMemoryRanges() const {
   return std::set<CheckedRange<uint64_t>>();
 }
 
+std::vector<const UserMinidumpStream*>
+ModuleSnapshotMac::CustomMinidumpStreams() const {
+  return std::vector<const UserMinidumpStream*>();
+}
+
 }  // namespace internal
 }  // namespace crashpad
diff --git a/snapshot/mac/module_snapshot_mac.h b/snapshot/mac/module_snapshot_mac.h
index 0c6bd69a..23904a5e 100644
--- a/snapshot/mac/module_snapshot_mac.h
+++ b/snapshot/mac/module_snapshot_mac.h
@@ -80,6 +80,7 @@ class ModuleSnapshotMac final : public ModuleSnapshot {
   std::vector<std::string> AnnotationsVector() const override;
   std::map<std::string, std::string> AnnotationsSimpleMap() const override;
   std::set<CheckedRange<uint64_t>> ExtraMemoryRanges() const override;
+  std::vector<const UserMinidumpStream*> CustomMinidumpStreams() const override;
 
  private:
   std::string name_;
diff --git a/snapshot/mac/process_types/crashpad_info.proctype b/snapshot/mac/process_types/crashpad_info.proctype
index 7d5383a3..90ed0d44 100644
--- a/snapshot/mac/process_types/crashpad_info.proctype
+++ b/snapshot/mac/process_types/crashpad_info.proctype
@@ -42,4 +42,7 @@ PROCESS_TYPE_STRUCT_BEGIN(CrashpadInfo)
 
   // SimpleStringDictionary*
   PROCESS_TYPE_STRUCT_MEMBER(Pointer, simple_annotations)
+
+  // UserDataStreamListEntry*
+  PROCESS_TYPE_STRUCT_MEMBER(Pointer, user_data_minidump_stream_head)
 PROCESS_TYPE_STRUCT_END(CrashpadInfo)
diff --git a/snapshot/minidump/module_snapshot_minidump.cc b/snapshot/minidump/module_snapshot_minidump.cc
index c83de596..f5132270 100644
--- a/snapshot/minidump/module_snapshot_minidump.cc
+++ b/snapshot/minidump/module_snapshot_minidump.cc
@@ -138,9 +138,17 @@ ModuleSnapshotMinidump::AnnotationsSimpleMap() const {
 std::set<CheckedRange<uint64_t>> ModuleSnapshotMinidump::ExtraMemoryRanges()
     const {
   INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+  NOTREACHED();  // https://crashpad.chromium.org/bug/10
   return std::set<CheckedRange<uint64_t>>();
 }
 
+std::vector<const UserMinidumpStream*>
+ModuleSnapshotMinidump::CustomMinidumpStreams() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+  NOTREACHED();  // https://crashpad.chromium.org/bug/10
+  return std::vector<const UserMinidumpStream*>();
+}
+
 bool ModuleSnapshotMinidump::InitializeModuleCrashpadInfo(
     FileReaderInterface* file_reader,
     const MINIDUMP_LOCATION_DESCRIPTOR*
diff --git a/snapshot/minidump/module_snapshot_minidump.h b/snapshot/minidump/module_snapshot_minidump.h
index dc375f03..3d63f2ac 100644
--- a/snapshot/minidump/module_snapshot_minidump.h
+++ b/snapshot/minidump/module_snapshot_minidump.h
@@ -77,6 +77,7 @@ class ModuleSnapshotMinidump final : public ModuleSnapshot {
   std::vector<std::string> AnnotationsVector() const override;
   std::map<std::string, std::string> AnnotationsSimpleMap() const override;
   std::set<CheckedRange<uint64_t>> ExtraMemoryRanges() const override;
+  std::vector<const UserMinidumpStream*> CustomMinidumpStreams() const override;
 
  private:
   // Initializes data carried in a MinidumpModuleCrashpadInfo structure on
diff --git a/snapshot/module_snapshot.h b/snapshot/module_snapshot.h
index 3a1c3216..3e5d18af 100644
--- a/snapshot/module_snapshot.h
+++ b/snapshot/module_snapshot.h
@@ -23,11 +23,35 @@
 #include <string>
 #include <vector>
 
+#include "base/memory/scoped_ptr.h"
 #include "util/misc/uuid.h"
 #include "util/numeric/checked_range.h"
+#include "snapshot/memory_snapshot.h"
 
 namespace crashpad {
 
+class MemorySnapshot;
+
+//! \brief Information describing a custom user data stream in a minidump.
+class UserMinidumpStream {
+ public:
+  //! \brief Constructs a UserMinidumpStream, takes ownership of \a memory.
+  UserMinidumpStream(uint32_t stream_type, MemorySnapshot* memory)
+      : memory_(memory), stream_type_(stream_type) {}
+
+  const MemorySnapshot* memory() const { return memory_.get(); }
+  uint32_t stream_type() const { return stream_type_; }
+
+ private:
+  //! \brief The memory representing the custom minidump stream.
+  scoped_ptr<MemorySnapshot> memory_;
+
+  //! \brief The stream type that the minidump stream will be tagged with.
+  uint32_t stream_type_;
+
+  DISALLOW_COPY_AND_ASSIGN(UserMinidumpStream);
+};
+
 //! \brief An abstract interface to a snapshot representing a code module
 //!     (binary image) loaded into a snapshot process.
 class ModuleSnapshot {
@@ -174,6 +198,15 @@ class ModuleSnapshot {
   //! \brief Returns a set of extra memory ranges specified in the module as
   //!     being desirable to include in the crash dump.
   virtual std::set<CheckedRange<uint64_t>> ExtraMemoryRanges() const = 0;
+
+  //! \brief Returns a list of custom minidump stream specified in the module to
+  //!     be included in the crash dump.
+  //!
+  //! \return The caller does not take ownership of the returned objects, they
+  //!     are scoped to the lifetime of the ModuleSnapshot object that they were
+  //!     obtained from.
+  virtual std::vector<const UserMinidumpStream*> CustomMinidumpStreams()
+      const = 0;
 };
 
 }  // namespace crashpad
diff --git a/snapshot/test/test_module_snapshot.cc b/snapshot/test/test_module_snapshot.cc
index c853a780..08776d65 100644
--- a/snapshot/test/test_module_snapshot.cc
+++ b/snapshot/test/test_module_snapshot.cc
@@ -98,5 +98,10 @@ std::set<CheckedRange<uint64_t>> TestModuleSnapshot::ExtraMemoryRanges() const {
   return extra_memory_ranges_;
 }
 
+std::vector<const UserMinidumpStream*>
+TestModuleSnapshot::CustomMinidumpStreams() const {
+  return custom_minidump_streams_;
+}
+
 }  // namespace test
 }  // namespace crashpad
diff --git a/snapshot/test/test_module_snapshot.h b/snapshot/test/test_module_snapshot.h
index bbe6193d..7589d628 100644
--- a/snapshot/test/test_module_snapshot.h
+++ b/snapshot/test/test_module_snapshot.h
@@ -24,6 +24,7 @@
 
 #include "base/macros.h"
 #include "snapshot/module_snapshot.h"
+#include "util/stdlib/pointer_container.h"
 
 namespace crashpad {
 namespace test {
@@ -79,6 +80,9 @@ class TestModuleSnapshot final : public ModuleSnapshot {
       const std::set<CheckedRange<uint64_t>>& extra_memory_ranges) {
     extra_memory_ranges_ = extra_memory_ranges;
   }
+  void AddCustomMinidumpStream(const UserMinidumpStream* stream) {
+    custom_minidump_streams_.push_back(stream);
+  }
 
   // ModuleSnapshot:
 
@@ -100,6 +104,7 @@ class TestModuleSnapshot final : public ModuleSnapshot {
   std::vector<std::string> AnnotationsVector() const override;
   std::map<std::string, std::string> AnnotationsSimpleMap() const override;
   std::set<CheckedRange<uint64_t>> ExtraMemoryRanges() const override;
+  std::vector<const UserMinidumpStream*> CustomMinidumpStreams() const override;
 
  private:
   std::string name_;
@@ -115,6 +120,7 @@ class TestModuleSnapshot final : public ModuleSnapshot {
   std::vector<std::string> annotations_vector_;
   std::map<std::string, std::string> annotations_simple_map_;
   std::set<CheckedRange<uint64_t>> extra_memory_ranges_;
+  PointerVector<const UserMinidumpStream> custom_minidump_streams_;
 
   DISALLOW_COPY_AND_ASSIGN(TestModuleSnapshot);
 };
diff --git a/snapshot/win/end_to_end_test.py b/snapshot/win/end_to_end_test.py
index 404d6d3a..a3506b64 100755
--- a/snapshot/win/end_to_end_test.py
+++ b/snapshot/win/end_to_end_test.py
@@ -290,6 +290,12 @@ def RunTests(cdb_path,
             r'\?\?\?\?\?\?\?\? \?\?\?\?\?\?\?\?',
             'extra memory removal')
 
+  out = CdbRun(cdb_path, dump_path, '.dumpdebug')
+  out.Check(r'type \?\?\? \(333333\), size 00001000',
+            'first user stream')
+  out.Check(r'type \?\?\? \(222222\), size 00000080',
+            'second user stream')
+
   if z7_dump_path:
     out = CdbRun(cdb_path, z7_dump_path, '.ecxr;lm')
     out.Check('This dump file has an exception of interest stored in it',
diff --git a/snapshot/win/module_snapshot_win.cc b/snapshot/win/module_snapshot_win.cc
index b86e2029..54856cc8 100644
--- a/snapshot/win/module_snapshot_win.cc
+++ b/snapshot/win/module_snapshot_win.cc
@@ -15,7 +15,9 @@
 #include "snapshot/win/module_snapshot_win.h"
 
 #include "base/strings/utf_string_conversions.h"
+#include "client/crashpad_info.h"
 #include "client/simple_address_range_bag.h"
+#include "snapshot/win/memory_snapshot_win.h"
 #include "snapshot/win/pe_image_annotations_reader.h"
 #include "snapshot/win/pe_image_reader.h"
 #include "util/misc/tri_state.h"
@@ -196,6 +198,24 @@ std::set<CheckedRange<uint64_t>> ModuleSnapshotWin::ExtraMemoryRanges() const {
   return ranges;
 }
 
+std::vector<const UserMinidumpStream*>
+ModuleSnapshotWin::CustomMinidumpStreams() const {
+  INITIALIZATION_STATE_DCHECK_VALID(initialized_);
+  streams_.clear();
+  if (process_reader_->Is64Bit()) {
+    GetCrashpadUserMinidumpStreams<process_types::internal::Traits64>(
+        &streams_);
+  } else {
+    GetCrashpadUserMinidumpStreams<process_types::internal::Traits32>(
+        &streams_);
+  }
+
+  std::vector<const UserMinidumpStream*> result;
+  for (const auto* stream : streams_)
+    result.push_back(stream);
+  return result;
+}
+
 template <class Traits>
 void ModuleSnapshotWin::GetCrashpadOptionsInternal(
     CrashpadInfoClientOptions* options) {
@@ -262,5 +282,32 @@ void ModuleSnapshotWin::GetCrashpadExtraMemoryRanges(
   }
 }
 
+template <class Traits>
+void ModuleSnapshotWin::GetCrashpadUserMinidumpStreams(
+    PointerVector<const UserMinidumpStream>* streams) const {
+  process_types::CrashpadInfo<Traits> crashpad_info;
+  if (!pe_image_reader_->GetCrashpadInfo(&crashpad_info))
+    return;
+
+  for (uint64_t cur = crashpad_info.user_data_minidump_stream_head; cur;) {
+    internal::UserDataMinidumpStreamListEntry list_entry;
+    if (!process_reader_->ReadMemory(
+          cur, sizeof(list_entry), &list_entry)) {
+      LOG(WARNING) << "could not read user data stream entry from "
+                   << base::UTF16ToUTF8(name_);
+      return;
+    }
+
+    scoped_ptr<internal::MemorySnapshotWin> memory(
+        new internal::MemorySnapshotWin());
+    memory->Initialize(
+        process_reader_, list_entry.base_address, list_entry.size);
+    streams->push_back(
+        new UserMinidumpStream(list_entry.stream_type, memory.release()));
+
+    cur = list_entry.next;
+  }
+}
+
 }  // namespace internal
 }  // namespace crashpad
diff --git a/snapshot/win/module_snapshot_win.h b/snapshot/win/module_snapshot_win.h
index 85aeb123..dd12ae8b 100644
--- a/snapshot/win/module_snapshot_win.h
+++ b/snapshot/win/module_snapshot_win.h
@@ -29,6 +29,7 @@
 #include "snapshot/win/process_reader_win.h"
 #include "util/misc/initialization_state.h"
 #include "util/misc/initialization_state_dcheck.h"
+#include "util/stdlib/pointer_container.h"
 #include "util/win/process_info.h"
 
 namespace crashpad {
@@ -86,6 +87,7 @@ class ModuleSnapshotWin final : public ModuleSnapshot {
   std::vector<std::string> AnnotationsVector() const override;
   std::map<std::string, std::string> AnnotationsSimpleMap() const override;
   std::set<CheckedRange<uint64_t>> ExtraMemoryRanges() const override;
+  std::vector<const UserMinidumpStream*> CustomMinidumpStreams() const override;
 
  private:
   template <class Traits>
@@ -95,6 +97,10 @@ class ModuleSnapshotWin final : public ModuleSnapshot {
   void GetCrashpadExtraMemoryRanges(
       std::set<CheckedRange<uint64_t>>* ranges) const;
 
+  template <class Traits>
+  void GetCrashpadUserMinidumpStreams(
+      PointerVector<const UserMinidumpStream>* streams) const;
+
   // Initializes vs_fixed_file_info_ if it has not yet been initialized, and
   // returns a pointer to it. Returns nullptr on failure, with a message logged
   // on the first call.
@@ -107,6 +113,8 @@ class ModuleSnapshotWin final : public ModuleSnapshot {
   ProcessReaderWin* process_reader_;  // weak
   time_t timestamp_;
   uint32_t age_;
+  // Too const-y: https://crashpad.chromium.org/bug/9.
+  mutable PointerVector<const UserMinidumpStream> streams_;
   InitializationStateDcheck initialized_;
 
   // VSFixedFileInfo() is logically const, but updates these members on the
diff --git a/snapshot/win/pe_image_reader.h b/snapshot/win/pe_image_reader.h
index 96529bf8..6e5ef7d7 100644
--- a/snapshot/win/pe_image_reader.h
+++ b/snapshot/win/pe_image_reader.h
@@ -45,6 +45,7 @@ struct CrashpadInfo {
   uint8_t padding_0;
   typename Traits::Pointer extra_address_ranges;
   typename Traits::Pointer simple_annotations;
+  typename Traits::Pointer user_data_minidump_stream_head;
 };
 
 }  // namespace process_types