Add queued_time_ms trace for events in message loop

base/location.cc

Index: base/location.cc
diff --git a/base/location.cc b/base/location.cc
index b5da027ee821ece54eb15d4c2e8143b3a462961b..404b64e1964b895c8363071d5e603d6ce102f9ae 100644
--- a/base/location.cc
+++ b/base/location.cc
@@ -2,6 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "base/location.h"
+#include "base/debug/trace_event.h"
+#include "base/json/string_escape.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/stringprintf.h"
 #include "build/build_config.h"
 
 #if defined(COMPILER_MSVC)
@@ -11,9 +16,31 @@ extern "C" {
 }
 #endif
 
-#include "base/location.h"
-#include "base/strings/string_number_conversions.h"
-#include "base/strings/stringprintf.h"
+namespace {
+
+class LocationConvertableToTraceFormat
+    : public base::debug::ConvertableToTraceFormat {
+ public:
+  LocationConvertableToTraceFormat(const char* function_name,
+                                   const char* file_name)
+      : function_name_(function_name),
+        file_name_(file_name) {
+  }
+
+  virtual void AppendAsTraceFormat(std::string* out) const OVERRIDE {
+    out->append("\"");
+    base::JsonDoubleQuote(function_name_, false, out);
+    out->append("@");
+    base::JsonDoubleQuote(file_name_, false, out);
+    out->append("\"");
+  }
+
+ private:
+  const char* function_name_;
+  const char* file_name_;
+};

[jar (doing other things), 2013/07/08 23:14:19]

nit: NO_DEFAULT_COPY_OR_ASSIGN

+
+}  // namespace
 
 namespace tracked_objects {
 
@@ -39,6 +66,12 @@ std::string Location::ToString() const {
       base::IntToString(line_number_);
 }
 
+scoped_ptr<base::debug::ConvertableToTraceFormat>
+    Location::ToTraceFormat() const {
+  return scoped_ptr<base::debug::ConvertableToTraceFormat>(
+      new LocationConvertableToTraceFormat(function_name_, file_name_));
+}
+
 void Location::Write(bool display_filename, bool display_function_name,
                      std::string* output) const {
   base::StringAppendF(output, "%s[%d] ",