Implement WebVR presentation pausing for VR Shell Menu Mode

device/vr/android/gvr/gvr_gamepad_data_fetcher.cc

 // Copyright 2016 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.
 
 #include "device/vr/android/gvr/gvr_gamepad_data_fetcher.h"
 
 #include "base/strings/utf_string_conversions.h"
 
 #include "device/vr/android/gvr/gvr_delegate.h"
 #include "third_party/WebKit/public/platform/WebGamepads.h"
@@ skipping 10 matching lines @@
 
   const size_t str_to_copy = std::min(src.size(), dest_length - 1);
   memcpy(dest, src.data(), str_to_copy * sizeof(base::string16::value_type));
   dest[str_to_copy] = 0;
 }
 
 }  // namespace
 
 using namespace blink;
 
-GvrGamepadDataFetcher::Factory::Factory(GvrDelegate* delegate,
-                                        unsigned int display_id)
+GvrGamepadDataFetcher::Factory::Factory(
+    const base::WeakPtr<GvrDelegate>& delegate,
+    unsigned int display_id)
     : delegate_(delegate), display_id_(display_id) {}
 
 GvrGamepadDataFetcher::Factory::~Factory() {}
 
 std::unique_ptr<GamepadDataFetcher>
 GvrGamepadDataFetcher::Factory::CreateDataFetcher() {
-  return std::unique_ptr<GamepadDataFetcher>(
-      new GvrGamepadDataFetcher(delegate_, display_id_));
+  if (!delegate_)
+    return nullptr;
+  return base::MakeUnique<GvrGamepadDataFetcher>(delegate_.get(), display_id_);
 }
 
 GamepadSource GvrGamepadDataFetcher::Factory::source() {
   return GAMEPAD_SOURCE_GVR;
 }
 
 GvrGamepadDataFetcher::GvrGamepadDataFetcher(GvrDelegate* delegate,
                                              unsigned int display_id)
     : display_id_(display_id) {
   gvr::GvrApi* gvr_api = delegate->gvr_api();
@@ skipping 92 matching lines @@
     return;
 
   if (paused) {
     controller_api_->Pause();
   } else {
     controller_api_->Resume();
   }
 }
 
 }  // namespace device