Implement WebVR presentation pausing for VR Shell Menu Mode

device/vr/android/gvr/gvr_gamepad_data_fetcher.cc

Index: device/vr/android/gvr/gvr_gamepad_data_fetcher.cc
diff --git a/device/vr/android/gvr/gvr_gamepad_data_fetcher.cc b/device/vr/android/gvr/gvr_gamepad_data_fetcher.cc
index 17bc49a7a358822c037493cbef2544a44c8ec9dd..0e8ec4a0ea5c6ca12fb3f13e1c04f7b5e3fc1e7f 100644
--- a/device/vr/android/gvr/gvr_gamepad_data_fetcher.cc
+++ b/device/vr/android/gvr/gvr_gamepad_data_fetcher.cc
@@ -28,7 +28,7 @@ void CopyToWebUString(blink::WebUChar* dest,
 
 using namespace blink;
 
-GvrGamepadDataFetcher::Factory::Factory(GvrDelegate* delegate,
+GvrGamepadDataFetcher::Factory::Factory(base::WeakPtr<GvrDelegate> delegate,
                                         unsigned int display_id)
     : delegate_(delegate), display_id_(display_id) {}
 
@@ -36,8 +36,10 @@ GvrGamepadDataFetcher::Factory::~Factory() {}
 
 std::unique_ptr<GamepadDataFetcher>
 GvrGamepadDataFetcher::Factory::CreateDataFetcher() {
+  if (!delegate_)
+    return std::unique_ptr<GamepadDataFetcher>(nullptr);

[dcheng, 2016/11/12 02:03:31]

Nit: Just return nullptr_ should be sufficient here (and the next line should be
base::MakeUnique<...>(...) if you're up for a little local cleanup.

[mthiesse, 2016/11/14 16:41:38]

Done.

   return std::unique_ptr<GamepadDataFetcher>(
-      new GvrGamepadDataFetcher(delegate_, display_id_));
+      new GvrGamepadDataFetcher(delegate_.get(), display_id_));
 }
 
 GamepadSource GvrGamepadDataFetcher::Factory::source() {