Pause drawing webvr when the App button is pressed

chrome/browser/android/vr_shell/ui_scene_manager_unittest.cc

+// Copyright 2017 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 "chrome/browser/android/vr_shell/ui_scene_manager.h"
+
+#include "base/macros.h"
+#include "chrome/browser/android/vr_shell/ui_scene.h"
+#include "chrome/browser/android/vr_shell/vr_browser_interface.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace vr_shell {
+
+namespace {
+
+class MockBrowserInterface : public VrBrowserInterface {
+ public:
+  MockBrowserInterface() : weak_ptr_factory_(this) {}
+  ~MockBrowserInterface() override {}
+
+  base::WeakPtr<VrBrowserInterface> GetWeakPtr() {
+    return weak_ptr_factory_.GetWeakPtr();
+  }
+
+  MOCK_METHOD1(OnContentPaused, void(bool));
+
+ private:
+  base::WeakPtrFactory<VrBrowserInterface> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(MockBrowserInterface);
+};
+
+}  // namespace
+
+class UiSceneManagerTest : public testing::Test {
+ public:
+  void SetUp() override {
+    browser_ = base::MakeUnique<MockBrowserInterface>();
+    scene_ = base::MakeUnique<UiScene>();
+    manager_ =
+        base::MakeUnique<UiSceneManager>(browser_->GetWeakPtr(), scene_.get());
+  }
+
+ protected:
+  std::unique_ptr<MockBrowserInterface> browser_;
+  std::unique_ptr<UiScene> scene_;
+  std::unique_ptr<UiSceneManager> manager_;
+};
+
+TEST_F(UiSceneManagerTest, ContentPausesOnAppButtonClick) {
+  EXPECT_TRUE(scene_->GetWebVrRenderingEnabled());
+
+  // Clicking app button once should pause content rendering.
+  EXPECT_CALL(*browser_, OnContentPaused(true)).Times(1);
+  manager_->OnAppButtonClicked();
+  EXPECT_FALSE(scene_->GetWebVrRenderingEnabled());
+
+  // Clicking it again should resume content rendering.
+  EXPECT_CALL(*browser_, OnContentPaused(false)).Times(1);

[cjgrant, 2017/05/03 14:40:38]

This looks good, but I think it touches on the ordering behaviour of mocks. 
See:
https://github.com/google/googletest/blob/master/googlemock/docs/ForDummies.m...

For kicks, can you see if this test still passes if you reverse the expectations
to 'false' then 'true'?  If it falsely passes, the doc shows how to make this
work right.

[ymalik, 2017/05/03 20:26:38]

Totally. In fact it helped me find a bug in the code :P

+  manager_->OnAppButtonClicked();
+  EXPECT_TRUE(scene_->GetWebVrRenderingEnabled());
+}
+
+}  // namespace vr_shell