Remove WebGraphicsContext3D getter from cc::ContextProvider

cc/output/context_provider.h

Index: cc/output/context_provider.h
diff --git a/cc/output/context_provider.h b/cc/output/context_provider.h
index 0b6d48232c60adef0e9fdaa9749d5fa25545b6c9..5a7e2c90f3a64529a2491ef110e1cd4d13ebea06 100644
--- a/cc/output/context_provider.h
+++ b/cc/output/context_provider.h
@@ -12,7 +12,6 @@
 
 class GrContext;
 
-namespace blink { class WebGraphicsContext3D; }
 namespace gpu {
 class ContextSupport;
 namespace gles2 { class GLES2Interface; }
@@ -29,7 +28,6 @@ class ContextProvider : public base::RefCountedThreadSafe<ContextProvider> {
   // from the same thread.
   virtual bool BindToCurrentThread() = 0;
 
-  virtual blink::WebGraphicsContext3D* Context3d() = 0;
   virtual gpu::gles2::GLES2Interface* ContextGL() = 0;
   virtual gpu::ContextSupport* ContextSupport() = 0;
   virtual class GrContext* GrContext() = 0;