Changes to enable HTML5 autoplay for voice search.

chrome/android/java/src/org/chromium/chrome/browser/VoiceSearchTabHelper.java

Index: chrome/android/java/src/org/chromium/chrome/browser/VoiceSearchTabHelper.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/VoiceSearchTabHelper.java b/chrome/android/java/src/org/chromium/chrome/browser/VoiceSearchTabHelper.java
new file mode 100644
index 0000000000000000000000000000000000000000..1204fbbf786299ba058946aea9f7b1bcdf7a85ab
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/VoiceSearchTabHelper.java
@@ -0,0 +1,37 @@
+// 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.
+
+package org.chromium.chrome.browser;
+
+import org.chromium.content.browser.ContentViewCore;
+import org.chromium.content.browser.WebContents;
+import org.chromium.content.browser.WebContentsObserverAndroid;
+
+/**
+ * Tab helper to toggle autoplay for media autoplay. Autoplay is enabled from native in
+ * ChromeContentBrowserClient for voice search URLs.
+ */
+public class VoiceSearchTabHelper extends WebContentsObserverAndroid {
+    private static final String TAG = "VoiceSearchTabHelper";
+    private long mNativeVoiceSearchTabHelper;
+
+    /**
+     * Create an instance of VoiceSearchTabHelper.
+     *
+     * @param contentViewCore ContentViewCore to update media autoplay status.
+     */
+    public VoiceSearchTabHelper(ContentViewCore contentViewCore) {
+        super(contentViewCore);
+        mNativeVoiceSearchTabHelper = nativeInit(contentViewCore.getWebContents());

[Ted C, 2013/12/17 00:59:00]

If you wanted, you could also store a pointer to the WebContents here and make
all the native side a single static method to toggle the enabled state (without
needing a native init).

[apiccion, 2013/12/17 21:17:11]

Done.

+    }
+
+    @Override
+    public void navigationEntryCommitted() {

[Ted C, 2013/12/17 00:59:00]

Hmm...what happens if the navigation entry being committed is for the google
search url?  Is it possible this will disable the autoplay before the audio has
had a chance to start playing?  

[apiccion, 2013/12/17 21:17:11]

Done.

+        nativeSetMediaAutoplayEnabled(mNativeVoiceSearchTabHelper, false);
+    }
+
+    private native long nativeInit(WebContents webContents);
+    private native void nativeSetMediaAutoplayEnabled(long nativeVoiceSearchTabHelper,
+            boolean isEnabled);
+}