Changes to enable HTML5 autoplay for voice search.

chrome/browser/android/voice_search_tab_helper.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 "chrome/browser/android/voice_search_tab_helper.h"
+
+#include "chrome/browser/google/google_util.h"
+#include "content/public/browser/render_view_host.h"
+#include "content/public/browser/web_contents.h"
+#include "jni/VoiceSearchTabHelper_jni.h"
+#include "webkit/common/webpreferences.h"
+
+using content::WebContents;
+
+// Register native methods
+bool RegisterVoiceSearchTabHelper(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+static void UpdateAutoplayStatus(JNIEnv* env,
+                                 jobject obj,
+                                 jobject j_web_contents) {
+  WebContents* web_contents = WebContents::FromJavaWebContents(j_web_contents);
+  content::RenderViewHost* host = web_contents->GetRenderViewHost();

[David Trainor- moved to gerrit, 2013/12/30 18:14:30]

IIRC they're refactoring RenderViewHost to RenderFrameHost?  There was a PSA
sent out about this earlier today.  Maybe email the mailing list on the PSA or
look at that crbug to see how to use their new RenderFrameHost?  If it's not
ready yet, just file a bug / track the work for you to help out on the refactor
in this file.

[apiccion, 2013/12/31 18:52:46]

The PSA is here:
https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/9qTMXFyPN_g

It doesn't look like WebContentsObserver will be modified in a heavy way.

The question is: What's going to happen to GetWebkitPreferences and
UpdateWebkitPreferences? The latter does not exist in RFH (yet?).

I've reached out to site-isolation-dev@chromium.org with questions.

[apiccion, 2014/01/02 17:59:09]

They say it will probably move into WebContents since it's a per-page property.
Should be an easy refactor once that lands.

On 2013/12/31 18:52:46, apiccion wrote:

+  WebPreferences prefs = host->GetWebkitPreferences();
+
+  // Handle the case where media autoplay has been enabled from the command
+  // line. Or some other override is otherwise in place. This currently fixes
+  // performance tests (see tools/perf/benchmarks/media.py line 33).
+  //
+  // Note that GetWekitPreferences() is 'stateless'. It returns the default
+  // webkit preferences configuration from command line switches.
+  if (prefs.user_gesture_required_for_media_playback == false)
+    return;
+
+  prefs.user_gesture_required_for_media_playback =
+      !google_util::IsGoogleSearchUrl(web_contents->GetLastCommittedURL());
+  host->UpdateWebkitPreferences(prefs);
+}