diff --git a/minidump/minidump_location_descriptor_list_writer_test.cc b/minidump/minidump_location_descriptor_list_writer_test.cc
index 53a1272a..00743063 100644
--- a/minidump/minidump_location_descriptor_list_writer_test.cc
+++ b/minidump/minidump_location_descriptor_list_writer_test.cc
@@ -14,6 +14,7 @@
 
 #include "minidump/minidump_location_descriptor_list_writer.h"
 
+#include "base/format_macros.h"
 #include "base/strings/stringprintf.h"
 #include "gtest/gtest.h"
 #include "minidump/test/minidump_location_descriptor_list_test_util.h"
@@ -95,7 +96,7 @@ TEST(MinidumpLocationDescriptorListWriter, ThreeChildren) {
   ASSERT_TRUE(list);
 
   for (size_t index = 0; index < arraysize(kValues); ++index) {
-    SCOPED_TRACE(base::StringPrintf("index %zu", index));
+    SCOPED_TRACE(base::StringPrintf("index %" PRIuS, index));
 
     const uint32_t* child = MinidumpWritableAtLocationDescriptor<uint32_t>(
         file_writer.string(), list->children[index]);
diff --git a/minidump/minidump_memory_writer_test.cc b/minidump/minidump_memory_writer_test.cc
index 1aee35de..e77a0648 100644
--- a/minidump/minidump_memory_writer_test.cc
+++ b/minidump/minidump_memory_writer_test.cc
@@ -19,6 +19,7 @@
 #include <stdint.h>
 
 #include "base/basictypes.h"
+#include "base/format_macros.h"
 #include "base/strings/stringprintf.h"
 #include "gtest/gtest.h"
 #include "minidump/minidump_extensions.h"
@@ -347,7 +348,7 @@ TEST(MinidumpMemoryWriter, AddFromSnapshot) {
   ASSERT_EQ(3u, memory_list->NumberOfMemoryRanges);
 
   for (size_t index = 0; index < memory_list->NumberOfMemoryRanges; ++index) {
-    SCOPED_TRACE(base::StringPrintf("index %zu", index));
+    SCOPED_TRACE(base::StringPrintf("index %" PRIuS, index));
     ExpectMinidumpMemoryDescriptorAndContents(
         &expect_memory_descriptors[index],
         &memory_list->MemoryRanges[index],
diff --git a/minidump/minidump_module_writer_test.cc b/minidump/minidump_module_writer_test.cc
index 881f33c5..dd104a5a 100644
--- a/minidump/minidump_module_writer_test.cc
+++ b/minidump/minidump_module_writer_test.cc
@@ -20,6 +20,7 @@
 #include <string.h>
 #include <sys/types.h>
 
+#include "base/format_macros.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "gtest/gtest.h"
@@ -729,7 +730,7 @@ TEST(MinidumpModuleWriter, InitializeFromSnapshot) {
   ASSERT_EQ(3u, module_list->NumberOfModules);
 
   for (size_t index = 0; index < module_list->NumberOfModules; ++index) {
-    SCOPED_TRACE(base::StringPrintf("index %zu", index));
+    SCOPED_TRACE(base::StringPrintf("index %" PRIuS, index));
     ASSERT_NO_FATAL_FAILURE(ExpectModule(&expect_modules[index],
                                          &module_list->Modules[index],
                                          file_writer.string(),
diff --git a/minidump/minidump_rva_list_writer_test.cc b/minidump/minidump_rva_list_writer_test.cc
index e2b7d122..0754748a 100644
--- a/minidump/minidump_rva_list_writer_test.cc
+++ b/minidump/minidump_rva_list_writer_test.cc
@@ -14,6 +14,7 @@
 
 #include "minidump/minidump_rva_list_writer.h"
 
+#include "base/format_macros.h"
 #include "base/strings/stringprintf.h"
 #include "gtest/gtest.h"
 #include "minidump/test/minidump_rva_list_test_util.h"
@@ -87,7 +88,7 @@ TEST(MinidumpRVAListWriter, ThreeChildren) {
   ASSERT_TRUE(list);
 
   for (size_t index = 0; index < arraysize(kValues); ++index) {
-    SCOPED_TRACE(base::StringPrintf("index %zu", index));
+    SCOPED_TRACE(base::StringPrintf("index %" PRIuS, index));
 
     const uint32_t* child = MinidumpWritableAtRVA<uint32_t>(
         file_writer.string(), list->children[index]);
diff --git a/minidump/minidump_string_writer_test.cc b/minidump/minidump_string_writer_test.cc
index 730d5fed..2bc87180 100644
--- a/minidump/minidump_string_writer_test.cc
+++ b/minidump/minidump_string_writer_test.cc
@@ -22,6 +22,7 @@
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
+#include "base/format_macros.h"
 #include "base/strings/string16.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
@@ -73,7 +74,7 @@ TEST(MinidumpStringWriter, MinidumpUTF16StringWriter) {
 
   for (size_t index = 0; index < arraysize(kTestData); ++index) {
     SCOPED_TRACE(base::StringPrintf(
-        "index %zu, input %s", index, kTestData[index].input_string));
+        "index %" PRIuS ", input %s", index, kTestData[index].input_string));
 
     // Make sure that the expected output string with its NUL terminator fits in
     // the space provided.
@@ -120,8 +121,8 @@ TEST(MinidumpStringWriter, ConvertInvalidUTF8ToUTF16) {
   };
 
   for (size_t index = 0; index < arraysize(kTestData); ++index) {
-    SCOPED_TRACE(
-        base::StringPrintf("index %zu, input %s", index, kTestData[index]));
+    SCOPED_TRACE(base::StringPrintf(
+        "index %" PRIuS ", input %s", index, kTestData[index]));
     file_writer.Reset();
     crashpad::internal::MinidumpUTF16StringWriter string_writer;
     string_writer.SetUTF8(kTestData[index]);
@@ -183,7 +184,7 @@ TEST(MinidumpStringWriter, MinidumpUTF8StringWriter) {
 
   for (size_t index = 0; index < arraysize(kTestData); ++index) {
     SCOPED_TRACE(base::StringPrintf(
-        "index %zu, input %s", index, kTestData[index].string));
+        "index %" PRIuS ", input %s", index, kTestData[index].string));
 
     file_writer.Reset();
     crashpad::internal::MinidumpUTF8StringWriter string_writer;
diff --git a/minidump/minidump_thread_writer_test.cc b/minidump/minidump_thread_writer_test.cc
index f8fd43b4..3f41c7c0 100644
--- a/minidump/minidump_thread_writer_test.cc
+++ b/minidump/minidump_thread_writer_test.cc
@@ -19,6 +19,7 @@
 #include <sys/types.h>
 
 #include "base/compiler_specific.h"
+#include "base/format_macros.h"
 #include "base/strings/stringprintf.h"
 #include "gtest/gtest.h"
 #include "minidump/minidump_context_writer.h"
@@ -619,7 +620,7 @@ void RunInitializeFromSnapshotTest(bool thread_id_collision) {
 
   size_t memory_index = 0;
   for (size_t index = 0; index < thread_list->NumberOfThreads; ++index) {
-    SCOPED_TRACE(base::StringPrintf("index %zu", index));
+    SCOPED_TRACE(base::StringPrintf("index %" PRIuS, index));
 
     const MINIDUMP_MEMORY_DESCRIPTOR* observed_stack = nullptr;
     const MINIDUMP_MEMORY_DESCRIPTOR** observed_stack_p =
diff --git a/minidump/test/minidump_context_test_util.cc b/minidump/test/minidump_context_test_util.cc
index b410cd5c..a0e06400 100644
--- a/minidump/test/minidump_context_test_util.cc
+++ b/minidump/test/minidump_context_test_util.cc
@@ -15,6 +15,7 @@
 #include "minidump/test/minidump_context_test_util.h"
 
 #include "base/basictypes.h"
+#include "base/format_macros.h"
 #include "base/strings/stringprintf.h"
 #include "gtest/gtest.h"
 #include "snapshot/cpu_context.h"
@@ -183,7 +184,7 @@ void ExpectMinidumpContextFxsave(const FxsaveType* expected,
   for (size_t st_mm_index = 0;
        st_mm_index < arraysize(expected->st_mm);
        ++st_mm_index) {
-    SCOPED_TRACE(base::StringPrintf("st_mm_index %zu", st_mm_index));
+    SCOPED_TRACE(base::StringPrintf("st_mm_index %" PRIuS, st_mm_index));
     for (size_t byte = 0;
          byte < arraysize(expected->st_mm[st_mm_index].st);
          ++byte) {
@@ -201,7 +202,7 @@ void ExpectMinidumpContextFxsave(const FxsaveType* expected,
   for (size_t xmm_index = 0;
        xmm_index < arraysize(expected->xmm);
        ++xmm_index) {
-    SCOPED_TRACE(base::StringPrintf("xmm_index %zu", xmm_index));
+    SCOPED_TRACE(base::StringPrintf("xmm_index %" PRIuS, xmm_index));
     for (size_t byte = 0; byte < arraysize(expected->xmm[xmm_index]); ++byte) {
       EXPECT_EQ(expected->xmm[xmm_index][byte], observed->xmm[xmm_index][byte])
           << "byte " << byte;