Native memory histograms for the browser.

content/browser/browser_main_loop.cc

Index: content/browser/browser_main_loop.cc
diff --git a/content/browser/browser_main_loop.cc b/content/browser/browser_main_loop.cc
index b58a2cb2267779a56d004a1b0aa6ba3c07f5f733..da71a3a429fd2496212c7f565997ef764ad722af 100644
--- a/content/browser/browser_main_loop.cc
+++ b/content/browser/browser_main_loop.cc
@@ -46,6 +46,7 @@
 #include "net/socket/client_socket_factory.h"
 #include "net/socket/tcp_client_socket.h"
 #include "ui/base/clipboard/clipboard.h"
+#include "webkit/glue/webkit_glue.h"
 
 #if defined(USE_AURA)
 #include "content/browser/renderer_host/image_transport_factory.h"
@@ -222,6 +223,22 @@ void ImmediateShutdownAndExitProcess() {
   BrowserShutdownImpl::ImmediateShutdownAndExitProcess();
 }
 
+// For measuring memory usage after each task. Behind a command line flag.
+class BrowserMainLoop::MemoryObserver : public MessageLoop::TaskObserver {
+ public:
+  MemoryObserver() {}
+  virtual ~MemoryObserver() {}
+
+  virtual void WillProcessTask(base::TimeTicks time_posted) OVERRIDE {}
+
+  virtual void DidProcessTask(base::TimeTicks time_posted) OVERRIDE {
+    HISTOGRAM_MEMORY_KB("Memory.BrowserUsed", webkit_glue::MemoryUsageKB());
+  }
+ private:
+  DISALLOW_COPY_AND_ASSIGN(MemoryObserver);
+};
+
+
 // static
 media::AudioManager* BrowserMainLoop::GetAudioManager() {
   return g_current_browser_main_loop->audio_manager_.get();
@@ -368,6 +385,11 @@ void BrowserMainLoop::MainMessageLoopStart() {
           switches::kMediaPlayerInRenderProcess)));
   DataFetcherImplAndroid::Init(base::android::AttachCurrentThread());
 #endif
+
+  if (parsed_command_line_.HasSwitch(switches::kMemoryMetrics)) {
+    memory_observer_.reset(new MemoryObserver());
+    main_message_loop_->AddTaskObserver(memory_observer_.get());
+  }
 }
 
 void BrowserMainLoop::CreateThreads() {