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

chrome/browser/android/vr_shell/non_presenting_gvr_delegate.h

Index: chrome/browser/android/vr_shell/non_presenting_gvr_delegate.h
diff --git a/chrome/browser/android/vr_shell/non_presenting_gvr_delegate.h b/chrome/browser/android/vr_shell/non_presenting_gvr_delegate.h
index 0bf91043cc56fa11d6e7f6a99fb736c39cc07d81..d639257a84ba046ef636fb46d58de2cdabc8caa5 100644
--- a/chrome/browser/android/vr_shell/non_presenting_gvr_delegate.h
+++ b/chrome/browser/android/vr_shell/non_presenting_gvr_delegate.h
@@ -28,7 +28,12 @@ class NonPresentingGvrDelegate : public device::GvrDelegate,
 
   // GvrDelegate implementation
   void SetWebVRSecureOrigin(bool secure_origin) override {}
-  void SubmitWebVRFrame() override {}
+  void SubmitWebVRFrame(
+      int frame_index, const gpu::Mailbox&,
+      device::mojom::VRSubmitFrameClientPtr submit_client) override {
+    submit_client->OnSubmitFrameTransferred();
+    submit_client->OnSubmitFrameRendered();
+  }
   void UpdateWebVRTextureBounds(int16_t frame_index,
                                 const gvr::Rectf& left_bounds,
                                 const gvr::Rectf& right_bounds) override {}