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 7f1737af0a051a7a38263140612a7508ade444bc..134e4f5c44650fbf0fb557fb7011cf001aad6428 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;