Add a histogram to measure task execution time for the render thread.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/6670029

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@78728 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 29 insertions, 0 deletions

diff --git a/chrome/renderer/renderer_main.cc b/chrome/renderer/renderer_main.cc
index b04f7d3..06e71d3 100644
--- a/chrome/renderer/renderer_main.cc
+++ b/chrome/renderer/renderer_main.cc
@@ -17,8 +17,10 @@
 #include "base/metrics/stats_counters.h"
 #include "base/path_service.h"
 #include "base/process_util.h"
+#include "base/ref_counted.h"
 #include "base/string_util.h"
 #include "base/threading/platform_thread.h"
+#include "base/time.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_counters.h"
 #include "chrome/common/chrome_switches.h"
@@ -177,6 +179,31 @@ static void HandleRendererErrorTestParameters(const CommandLine& command_line) {
   }
 }
 
+// This is a simplified version of the browser Jankometer, which measures
+// the processing time of tasks on the render thread.
+class RendererMessageLoopObserver : public MessageLoop::TaskObserver {
+ public:
+  RendererMessageLoopObserver()
+      : process_times_(base::Histogram::FactoryGet(
+            "Chrome.ProcMsgL RenderThread",
+            1, 3600000, 50, base::Histogram::kUmaTargetedHistogramFlag)) {}
+  virtual ~RendererMessageLoopObserver() {}
+
+  virtual void WillProcessTask(const Task* task) {
+    begin_process_message_ = base::TimeTicks::Now();
+  }
+
+  virtual void DidProcessTask(const Task* task) {
+    if (begin_process_message_ != base::TimeTicks())
+      process_times_->AddTime(base::TimeTicks::Now() - begin_process_message_);
+  }
+
+ private:
+  base::TimeTicks begin_process_message_;
+  scoped_refptr<base::Histogram> process_times_;
+  DISALLOW_COPY_AND_ASSIGN(RendererMessageLoopObserver);
+};
+
 // mainline routine for running as the Renderer process
 int RendererMain(const MainFunctionParams& parameters) {
   TRACE_EVENT_BEGIN("RendererMain", 0, "");
@@ -239,6 +266,7 @@ int RendererMain(const MainFunctionParams& parameters) {
   base::StatsScope<base::StatsCounterTimer>
       startup_timer(chrome::Counters::renderer_main());
 
+  RendererMessageLoopObserver task_observer;
 #if defined(OS_MACOSX)
   // As long as we use Cocoa in the renderer (for the forseeable future as of
   // now; see http://crbug.com/13890 for info) we need to have a UI loop.
@@ -249,6 +277,7 @@ int RendererMain(const MainFunctionParams& parameters) {
   MessageLoop main_message_loop(RenderProcessImpl::InProcessPlugins() ?
               MessageLoop::TYPE_UI : MessageLoop::TYPE_DEFAULT);
 #endif
+  main_message_loop.AddTaskObserver(&task_observer);
 
   base::PlatformThread::SetName("CrRendererMain");