Send idle notifications to V8 after commit

content/renderer/gpu/render_widget_compositor.cc

Index: content/renderer/gpu/render_widget_compositor.cc
diff --git a/content/renderer/gpu/render_widget_compositor.cc b/content/renderer/gpu/render_widget_compositor.cc
index d21b85bcc42af66ba2ba9fe3263bac6ca0ce3aad..83f7c16c63072ac2fb11dfcde4c6e05ea37f157c 100644
--- a/content/renderer/gpu/render_widget_compositor.cc
+++ b/content/renderer/gpu/render_widget_compositor.cc
@@ -38,6 +38,7 @@
 #include "third_party/WebKit/public/platform/WebCompositeAndReadbackAsyncCallback.h"
 #include "third_party/WebKit/public/platform/WebSelectionBound.h"
 #include "third_party/WebKit/public/platform/WebSize.h"
+#include "third_party/WebKit/public/web/WebKit.h"
 #include "third_party/WebKit/public/web/WebWidget.h"
 #include "ui/gfx/frame_time.h"
 #include "ui/gl/gl_switches.h"
@@ -757,6 +758,7 @@ void RenderWidgetCompositor::DidBeginMainFrame() {
 }
 
 void RenderWidgetCompositor::BeginMainFrame(const cc::BeginFrameArgs& args) {
+  begin_main_frame_args_ = args;
   double frame_time = (args.frame_time - base::TimeTicks()).InSecondsF();
   WebBeginFrameArgs web_begin_frame_args = WebBeginFrameArgs(frame_time);
   widget_->webwidget()->beginFrame(web_begin_frame_args);
@@ -785,6 +787,16 @@ void RenderWidgetCompositor::WillCommit() {
 }
 
 void RenderWidgetCompositor::DidCommit() {
+  CommandLine* cmd = CommandLine::ForCurrentProcess();
+  if (cmd->HasSwitch(switches::kSendV8IdleNotificationAfterCommit)) {
+    int idle_time_for_gc =

[Hannes Payer (out of office), 2014/08/19 07:34:36]

Let's rename that variable to idle_time_in_ms. The embedder does not know what
v8 is doing in the idle time.

[ernstm, 2014/08/19 22:09:24]

Done.

+        std::max(0L, (begin_main_frame_args_.frame_time +
+                      begin_main_frame_args_.interval -
+                      base::TimeTicks::HighResNow()).InMilliseconds());
+    if (idle_time_for_gc)
+      blink::mainThreadIsolate()->IdleNotification(idle_time_for_gc);
+  }
+
   widget_->DidCommitCompositorFrame();
   widget_->didBecomeReadyForAdditionalInput();
 }