Do V8 GC ASAP if system memory is pressured

content/renderer/render_thread_impl.h

Index: content/renderer/render_thread_impl.h
diff --git a/content/renderer/render_thread_impl.h b/content/renderer/render_thread_impl.h
index ab67cd9ed12e8164975d6a62747f0ef4ae807a30..514c072a2540158054407b844bb90eb3bebf6e7d 100644
--- a/content/renderer/render_thread_impl.h
+++ b/content/renderer/render_thread_impl.h
@@ -31,6 +31,7 @@
 #include "net/base/network_change_notifier.h"
 #include "third_party/WebKit/public/platform/WebConnectionType.h"
 #include "ui/gfx/native_widget_types.h"
+#include "v8/include/v8.h"
 
 #if defined(OS_MACOSX)
 #include "third_party/WebKit/public/web/mac/WebScrollbarTheme.h"
@@ -517,6 +518,9 @@ class CONTENT_EXPORT RenderThreadImpl
 
   void ReleaseFreeMemory();
 
+  void IsMemoryPressured(bool memory_pressured);
+  static void OnV8InterruptCallback(v8::Isolate* isolate, void* data);
+
   scoped_ptr<WebGraphicsContext3DCommandBufferImpl> CreateOffscreenContext3d();
 
   // These objects live solely on the render thread.
@@ -703,6 +707,8 @@ class CONTENT_EXPORT RenderThreadImpl
       PendingRenderFrameConnectMap;
   PendingRenderFrameConnectMap pending_render_frame_connects_;
 
+  bool is_v8_need_gc_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderThreadImpl);
 };