Allow autoplay unmuted for WebAPK in the manifest scope

chrome/browser/android/tab_android.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_BROWSER_ANDROID_TAB_ANDROID_H_
 #define CHROME_BROWSER_ANDROID_TAB_ANDROID_H_
 
 #include <jni.h>
 #include <stdint.h>
 
@@ skipping 213 matching lines @@
   // TODO(dtrainor): Remove this, pull content_layer() on demand.
   void AttachToTabContentManager(
       JNIEnv* env,
       const base::android::JavaParamRef<jobject>& obj,
       const base::android::JavaParamRef<jobject>& jtab_content_manager);
 
   bool HasPrerenderedUrl(JNIEnv* env,
                          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);
 
  private:
   prerender::PrerenderManager* GetPrerenderManager() const;
 
   JavaObjectWeakGlobalRef weak_java_tab_;
 
   // The identifier used by session restore for this tab.
   SessionID session_tab_id_;
 
   // Identifier of the window the tab is in.
   SessionID session_window_id_;
 
   content::NotificationRegistrar notification_registrar_;
 
   scoped_refptr<cc::Layer> content_layer_;
   android::TabContentManager* tab_content_manager_;
 
   std::unique_ptr<content::WebContents> web_contents_;
   std::unique_ptr<android::TabWebContentsDelegateAndroid>
       web_contents_delegate_;
 
   std::unique_ptr<browser_sync::SyncedTabDelegateAndroid> synced_tab_delegate_;
 
+  std::string webapp_manifest_scope_;
+
   DISALLOW_COPY_AND_ASSIGN(TabAndroid);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_TAB_ANDROID_H_