Revert of WebVR compositor bypass via BrowserMain context + mailbox

chrome/browser/android/vr_shell/mailbox_to_surface_bridge.h

-// Copyright 2017 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef CHROME_BROWSER_ANDROID_VR_SHELL_MAILBOX_TO_SURFACE_BRIDGE_H_
-#define CHROME_BROWSER_ANDROID_VR_SHELL_MAILBOX_TO_SURFACE_BRIDGE_H_
-
-#include "base/memory/weak_ptr.h"
-
-namespace gl {
-class SurfaceTexture;
-}
-
-namespace gpu {
-struct MailboxHolder;
-namespace gles2 {
-class GLES2Interface;
-}
-}
-
-namespace cc {
-class ContextProvider;
-}
-
-namespace vr_shell {
-
-class MailboxToSurfaceBridge {
- public:
-  MailboxToSurfaceBridge();
-  ~MailboxToSurfaceBridge();
-
-  void CreateSurface(gl::SurfaceTexture*);
-
-  void ResizeSurface(int width, int height);
-
-  // Returns true if swapped successfully. This can fail if the GL
-  // context isn't ready for use yet, in that case the caller
-  // won't get a new frame on the SurfaceTexture.
-  bool CopyMailboxToSurfaceAndSwap(const gpu::MailboxHolder& mailbox);
-
- private:
-  void OnContextAvailable(scoped_refptr<cc::ContextProvider>);
-  void InitializeRenderer();
-  void DestroyContext();
-  void DrawQuad(unsigned int textureHandle);
-
-  scoped_refptr<cc::ContextProvider> context_provider_;
-  gpu::gles2::GLES2Interface* gl_ = nullptr;
-  int surface_handle_ = 0;
-
-  // Saved state for a pending resize, the dimensions are only
-  // valid if needs_resize_ is true.
-  bool needs_resize_ = false;
-  int resize_width_;
-  int resize_height_;
-
-  // Must be last.
-  base::WeakPtrFactory<MailboxToSurfaceBridge> weak_ptr_factory_;
-};
-
-}  // namespace vr_shell
-
-#endif  // CHROME_BROWSER_ANDROID_VR_SHELL_MAILBOX_TO_SURFACE_BRIDGE_H_