[ios] Adds a provider API for AudioSessionController.

ios/public/provider/chrome/browser/chrome_browser_provider.h

 // 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.
 
 #ifndef IOS_PUBLIC_PROVIDER_CHROME_BROWSER_CHROME_BROWSER_PROVIDER_H_
 #define IOS_PUBLIC_PROVIDER_CHROME_BROWSER_CHROME_BROWSER_PROVIDER_H_
 
 #include <CoreGraphics/CoreGraphics.h>
 #import <Foundation/Foundation.h>
 #include <stddef.h>
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/memory/ref_counted.h"
 #include "components/favicon_base/favicon_callback.h"
 
 class AutocompleteProvider;
 class GURL;
 class InfoBarViewDelegate;
 class PrefRegistrySimple;
 class PrefService;
+class VoiceSearchProvider;
 
 namespace autofill {
 class CardUnmaskPromptController;
 class CardUnmaskPromptView;
 }
 
 namespace net {
 class URLRequestContextGetter;
 }
 
@@ skipping 99 matching lines @@
   // is not yet available through web::WebState.
   // TODO(rohitrao): Change from |id| to |Tab*| once Tab is moved into the
   // Chromium tree.
   virtual void AttachTabHelpers(web::WebState* web_state, id tab) const;
 
   // Returns whether safe browsing is enabled. See the comment on
   // metrics_services_manager_client.h for details on |on_update_callback|.
   virtual bool IsSafeBrowsingEnabled(const base::Closure& on_update_callback);
 
   // Returns the list of available voice search languages.
+  // TODO(rohitrao): Remove once callers are going through VoiceSearchProvider.
   virtual NSArray* GetAvailableVoiceSearchLanguages() const;
 
+  // Returns an instance of the voice search provider, if one exists.
+  virtual VoiceSearchProvider* GetVoiceSearchProvider() const;
+
   // Returns the SyncedWindowDelegatesGetter implementation.
   virtual std::unique_ptr<sync_sessions::SyncedWindowDelegatesGetter>
   CreateSyncedWindowDelegatesGetter(ios::ChromeBrowserState* browser_state);
 };
 
 }  // namespace ios
 
 #endif  // IOS_PUBLIC_PROVIDER_CHROME_BROWSER_CHROME_BROWSER_PROVIDER_H_