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..feb3597fc74166866977f0ca4c5beb8939e9cb64 100644
--- a/chrome/browser/android/vr_shell/non_presenting_gvr_delegate.h
+++ b/chrome/browser/android/vr_shell/non_presenting_gvr_delegate.h
@@ -28,10 +28,18 @@ class NonPresentingGvrDelegate : public device::GvrDelegate,
 
   // GvrDelegate implementation
   void SetWebVRSecureOrigin(bool secure_origin) override {}
-  void SubmitWebVRFrame() override {}
+  void SubmitWebVRFrame(
+      int16_t frame_index,
+      const gpu::Mailbox& mailbox,
+      const gpu::SyncToken& sync_token,
+      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 {}
+                                const gvr::Rectf& right_bounds,
+                                const gvr::Sizei& source_size) override {}
   void OnVRVsyncProviderRequest(
       device::mojom::VRVSyncProviderRequest request) override;
   void UpdateVSyncInterval(int64_t timebase_nanos,