Plumb audio muting state to guest web-contents.

chrome/browser/apps/guest_view/web_view_browsertest.cc

 // Copyright 2013 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 <queue>
 #include <utility>
 
 #include "base/location.h"
 #include "base/macros.h"
 #include "base/path_service.h"
@@ skipping 727 matching lines @@
  protected:
   void SetUpCommandLine(base::CommandLine* command_line) override {
     WebViewTest::SetUpCommandLine(command_line);
     command_line->AppendSwitchASCII(switches::kForceDeviceScaleFactor,
                                     base::StringPrintf("%f", scale()));
   }
 
   static float scale() { return 2.0f; }
 };
 
+class WebContentsAudioMutedObserver : public content::WebContentsObserver {
+ public:
+  WebContentsAudioMutedObserver(content::WebContents* web_contents,
+                                const base::Closure& muted_callback)
+      : WebContentsObserver(web_contents),
+        muted_callback_(muted_callback),
+        muting_update_observed_(false) {
+  }
+
+  // WebContentsObserver.
+  void DidUpdateAudioMutingState(bool muted) override {
+    muting_update_observed_ = true;
+    muted_callback_.Run();
+  }
+
+  bool muting_update_observed() { return muting_update_observed_; }
+
+ private:
+  base::Closure muted_callback_;
+  bool muting_update_observed_;
+
+  DISALLOW_COPY_AND_ASSIGN(WebContentsAudioMutedObserver);
+};
+
+IN_PROC_BROWSER_TEST_F(WebViewTest, AudioMutesWhileAttached) {
+  LoadAppWithGuest("web_view/simple");
+
+  content::WebContents* embedder = GetEmbedderWebContents();
+  content::WebContents* guest = GetGuestWebContents();
+
+  EXPECT_FALSE(embedder->IsAudioMuted());
+  EXPECT_FALSE(guest->IsAudioMuted());
+
+  embedder->SetAudioMuted(true);
+  EXPECT_TRUE(embedder->IsAudioMuted());
+  EXPECT_TRUE(guest->IsAudioMuted());
+
+  embedder->SetAudioMuted(false);
+  EXPECT_FALSE(embedder->IsAudioMuted());
+  EXPECT_FALSE(guest->IsAudioMuted());

[Charlie Reis, 2016/01/06 22:13:51]

Is it possible to mute a guest without muting the embedder?  Just wondering if
we should test what happens in that case (and if so, what happens if the
embedder is then muted and unmuted).

[wjmaclean, 2016/01/06 22:36:09]

At present there is no pathway to mute a guest directly, i.e. the only pathway
involves muting the embedder.

[Charlie Reis, 2016/01/07 00:11:02]

Acknowledged.

+}
+
+IN_PROC_BROWSER_TEST_F(WebViewTest, AudioMutesOnAttach) {
+  LoadAndLaunchPlatformApp("web_view/app_creates_webview",
+                           "WebViewTest.LAUNCHED");
+  content::WebContents* embedder = GetEmbedderWebContents();
+  embedder->SetAudioMuted(true);
+  EXPECT_TRUE(embedder->IsAudioMuted());
+
+  SendMessageToEmbedder("create-guest");
+  content::WebContents* guest =
+      GetGuestViewManager()->WaitForSingleGuestCreated();
+
+  EXPECT_TRUE(embedder->IsAudioMuted());
+  scoped_refptr<content::MessageLoopRunner> loop_runner(
+      new content::MessageLoopRunner);
+  WebContentsAudioMutedObserver observer(guest, loop_runner->QuitClosure());
+  // If the guest hasn't attached yet, it may not have received the muting
+  // update, in which case we should wait until it does.
+  if (!guest->IsAudioMuted() && !observer.muting_update_observed())

[Charlie Reis, 2016/01/06 22:13:51]

observer.muting_update_observed() can't be true here, can it?  We just created
the observer and it hasn't gotten a chance to observe anything.

[wjmaclean, 2016/01/06 22:36:09]

I suspect you're right, but I left the check in for safety. I can remove it if
you prefer.

+    loop_runner->Run();

[Charlie Reis, 2016/01/06 22:13:51]

nit: Most of the test observer classes I'm familiar with (e.g.,
TestNavigationObserver) keep the MessageLoopRunner internally and have a Wait
method to expose it.  Maybe that would be a bit cleaner here?

[wjmaclean, 2016/01/06 22:36:09]

Sure, I can do that.

+  EXPECT_TRUE(guest->IsAudioMuted());
+}
+
 // This test verifies that hiding the guest triggers WebContents::WasHidden().
 IN_PROC_BROWSER_TEST_F(WebViewVisibilityTest, GuestVisibilityChanged) {
   LoadAppWithGuest("web_view/visibility_changed");
 
   scoped_refptr<content::MessageLoopRunner> loop_runner(
       new content::MessageLoopRunner);
   WebContentsHiddenObserver observer(GetGuestWebContents(),
                                      loop_runner->QuitClosure());
 
   // Handled in platform_apps/web_view/visibility_changed/main.js
@@ skipping 2197 matching lines @@
   // 4 tasks expected. The order is arbitrary.
   // Tab: about:blank,
   // Background Page: <webview> task manager test,
   // App: <webview> task manager test,
   // Webview: WebViewed test content.
   EXPECT_EQ(4U, task_manager.tasks().size());
   EXPECT_TRUE(HasExpectedGuestTask(task_manager, guest_contents));
 }
 
 #endif  // defined(ENABLE_TASK_MANAGER)