[Media Router] Implement MediaRouterAction + MediaRouterUI tests.

chrome/browser/ui/views/media_router/media_router_ui_browsertest.cc

+// Copyright 2015 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/ui/browser.h"
+#include "chrome/browser/ui/browser_commands.h"
+#include "chrome/browser/ui/tabs/tab_strip_model.h"
+#include "chrome/browser/ui/toolbar/media_router_action.h"
+#include "chrome/browser/ui/toolbar/toolbar_action_view_delegate.h"
+#include "chrome/browser/ui/views/frame/browser_view.h"
+#include "chrome/browser/ui/views/toolbar/browser_actions_container.h"
+#include "chrome/browser/ui/views/toolbar/toolbar_action_view.h"
+#include "chrome/browser/ui/views/toolbar/toolbar_view.h"
+#include "chrome/test/base/in_process_browser_test.h"
+#include "chrome/test/base/ui_test_utils.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/test/test_navigation_observer.h"
+#include "content/public/test/test_utils.h"
+
+namespace media_router {
+
+class MediaRouterUIBrowserTest : public InProcessBrowserTest {
+ public:
+  MediaRouterUIBrowserTest() {}
+  ~MediaRouterUIBrowserTest() override {}
+
+  void SetUpOnMainThread() override {
+    InProcessBrowserTest::SetUpOnMainThread();
+
+    BrowserActionsContainer* main_bar =

[Peter Kasting, 2015/06/04 00:17:53]

Nit: I think |browser_actions| might be a better name for this, since it matches
the helper function used to get it, and "main bar" is multiply confusing ("main"
implies there's a "secondary" somewhere, and "bar" implies this is the whole
toolbar).

You could also use |browser_actions_container| for more explicit clarity at the
cost of no longer matching the helper name.

[imcheng (use chromium acct), 2015/06/04 01:04:20]

Done.

+        BrowserView::GetBrowserViewForBrowser(browser())
+            ->toolbar()
+            ->browser_actions();
+    ASSERT_TRUE(main_bar);
+
+    mr_action_.reset(new MediaRouterAction);
+
+    // Sets delegate on |mr_action_|.
+    toolbar_action_view_.reset(new ToolbarActionView(
+        mr_action_.get(), browser()->profile(), main_bar));
+  }
+
+  void OpenMediaRouterDialog() {
+    content::TestNavigationObserver nav_observer(NULL);
+    nav_observer.StartWatchingNewWebContents();
+    mr_action_->ExecuteAction(true);
+    nav_observer.Wait();
+    nav_observer.StopWatchingNewWebContents();
+  }
+
+ protected:
+  // Must be initialized after |InProcessBrowserTest::SetUpOnMainThread|.
+  scoped_ptr<MediaRouterAction> mr_action_;

[Peter Kasting, 2015/06/04 00:17:53]

Nit: |media_router_action_| (or at least |router_action_|).  Avoid
abbreviations, especially ones like "mr" which look like "Mr." and thus are just
confusing.

[imcheng (use chromium acct), 2015/06/04 01:04:20]

Done.

+
+  // ToolbarActionView constructed to set the delegate on |mr_action|.
+  scoped_ptr<ToolbarActionView> toolbar_action_view_;
+};
+
+IN_PROC_BROWSER_TEST_F(MediaRouterUIBrowserTest, MediaRouterCommands) {

[Peter Kasting, 2015/06/04 00:17:53]

What is this actually testing?  The comments say what the test is doing but not
what we expect to happen and what the test overall accomplishes.

[imcheng (use chromium acct), 2015/06/04 01:04:20]

Renamed the function to be more explicit about expectations and added
supplementary comments to the test.

+  // We start off at about:blank page.
+  // Make sure there is 1 tab and media router is enabled.
+  ASSERT_EQ(1, browser()->tab_strip_model()->count());
+
+  OpenMediaRouterDialog();
+
+  // Reload the browser and wait.
+  content::TestNavigationObserver reload_observer(
+      browser()->tab_strip_model()->GetActiveWebContents());
+  chrome::Reload(browser(), CURRENT_TAB);
+  reload_observer.Wait();
+
+  OpenMediaRouterDialog();
+
+  // Navigate away and wait.
+  content::TestNavigationObserver nav_observer(
+      browser()->tab_strip_model()->GetActiveWebContents(), 1);
+  ui_test_utils::NavigateToURL(browser(), GURL("about:blank"));
+
+  nav_observer.Wait();
+
+  OpenMediaRouterDialog();
+}
+
+}  // namespace media_router