Re-land^2 WebVR compositor bypass via BrowserMain context + mailbox

chrome/browser/android/vr_shell/vr_shell_gl.h

Index: chrome/browser/android/vr_shell/vr_shell_gl.h
diff --git a/chrome/browser/android/vr_shell/vr_shell_gl.h b/chrome/browser/android/vr_shell/vr_shell_gl.h
index 1f82f88c4c292b42f0b2f7586a3c4d30cf0b0116..7ec43553ac4d3ff0c2191ed3e300eb46aa99b0a5 100644
--- a/chrome/browser/android/vr_shell/vr_shell_gl.h
+++ b/chrome/browser/android/vr_shell/vr_shell_gl.h
@@ -72,6 +72,7 @@ class VrShellGl : public device::mojom::VRVSyncProvider {
   void OnResume();
 
   void SetWebVrMode(bool enabled);
+  void CreateWebVRSurface();
   void CreateContentSurface();
   void ContentBoundsChanged(int width, int height);
   void ContentPhysicalBoundsChanged(int width, int height);
@@ -94,11 +95,13 @@ class VrShellGl : public device::mojom::VRVSyncProvider {
   void CreateVRDisplayInfo(
       const base::Callback<void(device::mojom::VRDisplayInfoPtr)>& callback,
       uint32_t device_id);
+  void ScheduleWebVRFrame(int frame_index);
+  void DropWebVRFrame(int frame_index);
 
  private:
   void GvrInit(gvr_context* gvr_api);
   void InitializeRenderer();
-  void DrawFrame();
+  void DrawFrame(int frame_index);
   void DrawVrShell(const gvr::Mat4f& head_pose, gvr::Frame& frame);
   void DrawUiView(const gvr::Mat4f* head_pose,
                   const std::vector<const ContentRectangle*>& elements,
@@ -121,6 +124,7 @@ class VrShellGl : public device::mojom::VRVSyncProvider {
   void CreateUiSurface();
   void OnUIFrameAvailable();
   void OnContentFrameAvailable();
+  void OnWebVRFrameAvailable();
   bool GetPixelEncodedFrameIndex(uint16_t* frame_index);
 
   void OnVSync();
@@ -136,6 +140,8 @@ class VrShellGl : public device::mojom::VRVSyncProvider {
   int ui_texture_id_ = 0;
   // samplerExternalOES texture data for main content image.
   int content_texture_id_ = 0;
+  // samplerExternalOES texture data for WebVR content image.
+  int webvr_texture_id_ = 0;
 
   std::unique_ptr<UiScene> scene_;
 
@@ -143,9 +149,12 @@ class VrShellGl : public device::mojom::VRVSyncProvider {
   scoped_refptr<gl::GLContext> context_;
   scoped_refptr<gl::SurfaceTexture> ui_surface_texture_;
   scoped_refptr<gl::SurfaceTexture> content_surface_texture_;
+  scoped_refptr<gl::SurfaceTexture> webvr_surface_texture_;
 
   std::unique_ptr<gl::ScopedJavaSurface> ui_surface_;
   std::unique_ptr<gl::ScopedJavaSurface> content_surface_;
+  std::unique_ptr<gl::ScopedJavaSurface> webvr_surface_;
+  int webvr_surface_handle_;
 
   std::unique_ptr<gvr::GvrApi> gvr_api_;
   std::unique_ptr<gvr::BufferViewportList> buffer_viewport_list_;
@@ -157,6 +166,9 @@ class VrShellGl : public device::mojom::VRVSyncProvider {
   std::unique_ptr<gvr::SwapChain> swap_chain_;
   using BoundsPair = std::pair<gvr::Rectf, gvr::Rectf>;
   std::queue<std::pair<uint8_t, BoundsPair>> pending_bounds_;
+  int requested_frames_ = 0;
+  int premature_received_frames_ = 0;
+  std::queue<uint16_t> pending_frames_;
 
   // Current sizes for the render buffers.
   gvr::Sizei render_size_primary_;
@@ -179,7 +191,6 @@ class VrShellGl : public device::mojom::VRVSyncProvider {
   gvr::Sizei ui_tex_physical_size_ = {0, 0};
 
   std::vector<gvr::Mat4f> webvr_head_pose_;
-  int webvr_texture_id_ = 0;
   bool web_vr_mode_;
   bool ready_to_draw_ = false;
   bool surfaceless_rendering_;