Add functionality to get default media device IDs from user preferences.

chrome/browser/ui/browser.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_UI_BROWSER_H_
 #define CHROME_BROWSER_UI_BROWSER_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 669 matching lines @@
                           bool user_gesture,
                           bool last_unlocked_by_target) override;
   void LostMouseLock() override;
   void RequestMediaAccessPermission(
       content::WebContents* web_contents,
       const content::MediaStreamRequest& request,
       const content::MediaResponseCallback& callback) override;
   bool CheckMediaAccessPermission(content::WebContents* web_contents,
                                   const GURL& security_origin,
                                   content::MediaStreamType type) override;
+  std::string GetDefaultMediaDeviceId(content::WebContents* web_contents,
+                                      content::MediaStreamType type) override;
   bool RequestPpapiBrokerPermission(
       content::WebContents* web_contents,
       const GURL& url,
       const base::FilePath& plugin_path,
       const base::Callback<void(bool)>& callback) override;
   gfx::Size GetSizeForNewRenderView(
       content::WebContents* web_contents) const override;
 
   // Overridden from CoreTabHelperDelegate:
   // Note that the caller is responsible for deleting |old_contents|.
@@ skipping 315 matching lines @@
   // The following factory is used for chrome update coalescing.
   base::WeakPtrFactory<Browser> chrome_updater_factory_;
 
   // The following factory is used to close the frame at a later time.
   base::WeakPtrFactory<Browser> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Browser);
 };
 
 #endif  // CHROME_BROWSER_UI_BROWSER_H_