Allow autoplay unmuted for WebAPK in the manifest scope

chrome/browser/android/tab_android.h

Index: chrome/browser/android/tab_android.h
diff --git a/chrome/browser/android/tab_android.h b/chrome/browser/android/tab_android.h
index 7b477b3cda4d535fe08f881a4875273936903bf4..12ee17ca5c34428c89bf490f413b9868056752e9 100644
--- a/chrome/browser/android/tab_android.h
+++ b/chrome/browser/android/tab_android.h
@@ -231,6 +231,15 @@ class TabAndroid : public CoreTabHelperDelegate,
                          const base::android::JavaParamRef<jobject>& obj,
                          const base::android::JavaParamRef<jstring>& url);
 
+  void SetWebappManifestScope(

[Ted C, 2017/02/15 05:07:25]

ideally, I'd rather not see this hang off of Tab.  It would be nicer to have it
in a user data that hangs off of web contents to make it more platform agnostic.

that is more plumbing and the like, so I won't push too strongly now.  If we end
up needing to add anything more for webapps, I'll push more strongly though.

[Zhiqiang Zhang (Slow), 2017/02/15 11:29:51]

I agree :)

+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      const base::android::JavaParamRef<jstring>& scope);
+
+  const std::string& GetWebappManifestScope() const {
+    return webapp_manifest_scope_;
+  }
+
   // Register the Tab's native methods through JNI.
   static bool RegisterTabAndroid(JNIEnv* env);
 
@@ -256,6 +265,8 @@ class TabAndroid : public CoreTabHelperDelegate,
 
   std::unique_ptr<browser_sync::SyncedTabDelegateAndroid> synced_tab_delegate_;
 
+  std::string webapp_manifest_scope_;
+
   DISALLOW_COPY_AND_ASSIGN(TabAndroid);
 };