Make BuildHandlerArgvStrings() return its result

This is more direct than using an out-parameter. Copy elision should
make it equally performant, and even in the absence of copy elision,
this would now be an inexpensive move operation.

Change-Id: Iaf0eb07b36c8e35ff8942fc422a22321bf5c3010
Reviewed-on: https://chromium-review.googlesource.com/1145495
Reviewed-by: Joshua Peraza <jperaza@chromium.org>
Commit-Queue: Mark Mentovai <mark@chromium.org>

build/whitespace.txt

@@ -1 +0,0 @@
-This is a whitespace file used to kick off jobs.

client/client_argv_handling.cc

@@ -27,38 +27,38 @@ std::string FormatArgumentString(const std::string& name,
 
 }  // namespace
 
-void BuildHandlerArgvStrings(
+std::vector<std::string> BuildHandlerArgvStrings(
     const base::FilePath& handler,
     const base::FilePath& database,
     const base::FilePath& metrics_dir,
     const std::string& url,
     const std::map<std::string, std::string>& annotations,
-    const std::vector<std::string>& arguments,
+    const std::vector<std::string>& arguments) {
-    std::vector<std::string>* argv_strings) {
+  std::vector<std::string> argv_strings(1, handler.value());
-  argv_strings->clear();
 
-  argv_strings->push_back(handler.value());
   for (const auto& argument : arguments) {
-    argv_strings->push_back(argument);
+    argv_strings.push_back(argument);
   }
 
   if (!database.empty()) {
-    argv_strings->push_back(FormatArgumentString("database", database.value()));
+    argv_strings.push_back(FormatArgumentString("database", database.value()));
   }
 
   if (!metrics_dir.empty()) {
-    argv_strings->push_back(
+    argv_strings.push_back(
         FormatArgumentString("metrics-dir", metrics_dir.value()));
   }
 
   if (!url.empty()) {
-    argv_strings->push_back(FormatArgumentString("url", url));
+    argv_strings.push_back(FormatArgumentString("url", url));
   }
 
   for (const auto& kv : annotations) {
-    argv_strings->push_back(
+    argv_strings.push_back(
         FormatArgumentString("annotation", kv.first + '=' + kv.second));
   }
+
+  return argv_strings;
 }
 
 void ConvertArgvStrings(const std::vector<std::string>& argv_strings,

client/client_argv_handling.h

@@ -28,16 +28,14 @@ namespace crashpad {
 //!
 //! See StartHandlerAtCrash() for documentation on the input arguments.
 //!
-//! \param[out] A argv_strings vector of arguments suitable for starting the
+//! \return A vector of arguments suitable for starting the handler with.
-//!     handler with.
+std::vector<std::string> BuildHandlerArgvStrings(
-void BuildHandlerArgvStrings(
     const base::FilePath& handler,
     const base::FilePath& database,
     const base::FilePath& metrics_dir,
     const std::string& url,
     const std::map<std::string, std::string>& annotations,
-    const std::vector<std::string>& arguments,
+    const std::vector<std::string>& arguments);
-    std::vector<std::string>* argv_strings);
 
 //! \brief Flattens a string vector into a const char* vector suitable for use
 //!     in an exec() call.

client/crashpad_client_fuchsia.cc

@@ -58,14 +58,8 @@ bool CrashpadClient::StartHandler(
     return false;
   }
 
-  std::vector<std::string> argv_strings;
+  std::vector<std::string> argv_strings = BuildHandlerArgvStrings(
-  BuildHandlerArgvStrings(handler,
+      handler, database, metrics_dir, url, annotations, arguments);
-                          database,
-                          metrics_dir,
-                          url,
-                          annotations,
-                          arguments,
-                          &argv_strings);
 
   std::vector<const char*> argv;
   ConvertArgvStrings(argv_strings, &argv);

client/crashpad_client_linux.cc

@@ -175,9 +175,8 @@ bool CrashpadClient::StartHandlerAtCrash(
     const std::string& url,
     const std::map<std::string, std::string>& annotations,
     const std::vector<std::string>& arguments) {
-  std::vector<std::string> argv;
+  std::vector<std::string> argv = BuildHandlerArgvStrings(
-  BuildHandlerArgvStrings(
+      handler, database, metrics_dir, url, annotations, arguments);
-      handler, database, metrics_dir, url, annotations, arguments, &argv);
 
   auto signal_handler = LaunchAtCrashHandler::Get();
   if (signal_handler->Initialize(&argv)) {
@@ -197,9 +196,8 @@ bool CrashpadClient::StartHandlerForClient(
     const std::map<std::string, std::string>& annotations,
     const std::vector<std::string>& arguments,
     int socket) {
-  std::vector<std::string> argv;
+  std::vector<std::string> argv = BuildHandlerArgvStrings(
-  BuildHandlerArgvStrings(
+      handler, database, metrics_dir, url, annotations, arguments);
-      handler, database, metrics_dir, url, annotations, arguments, &argv);
 
   argv.push_back(FormatArgumentInt("initial-client", socket));