Provide shared context to Platform API in renderer.

content/browser/renderer_host/compositor_impl_android.cc

Index: content/browser/renderer_host/compositor_impl_android.cc
diff --git a/content/browser/renderer_host/compositor_impl_android.cc b/content/browser/renderer_host/compositor_impl_android.cc
index 2b3a800f83734fb6741671e13717ce2d427f7d57..73eb374e56eff773a80913ad0b897891b697598a 100644
--- a/content/browser/renderer_host/compositor_impl_android.cc
+++ b/content/browser/renderer_host/compositor_impl_android.cc
@@ -328,11 +328,12 @@ void CompositorImpl::scheduleComposite() {
 }
 
 class NullContextProvider : public cc::ContextProvider {
-  virtual bool InitializeOnMainThread() { return false; }
-  virtual bool BindToCurrentThread() { return false; }
-  virtual WebKit::WebGraphicsContext3D* Context3d() { return NULL; }
-  virtual class GrContext* GrContext() { return NULL; }
-  virtual void VerifyContexts() {}
+  virtual bool InitializeOnMainThread() OVERRIDE { return false; }
+  virtual bool BindToCurrentThread() OVERRIDE { return false; }
+  virtual WebKit::WebGraphicsContext3D* Context3d() OVERRIDE { return NULL; }
+  virtual class GrContext* GrContext() OVERRIDE { return NULL; }
+  virtual void VerifyContexts() OVERRIDE {}
+  virtual bool DestroyedOnMainThread() OVERRIDE { return false; }
  protected:
   virtual ~NullContextProvider() {}
 };