[ios] Adds a provider API for AudioSessionController.

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

Index: ios/public/provider/chrome/browser/test_chrome_browser_provider.h
diff --git a/ios/public/provider/chrome/browser/test_chrome_browser_provider.h b/ios/public/provider/chrome/browser/test_chrome_browser_provider.h
index dffc1f627887e3d5a9ee8f96588160cb734a9e93..c87918597896e050a4ce75e9696e80f7f013d27c 100644
--- a/ios/public/provider/chrome/browser/test_chrome_browser_provider.h
+++ b/ios/public/provider/chrome/browser/test_chrome_browser_provider.h
@@ -13,8 +13,6 @@
 
 namespace ios {
 
-class TestUpdatableResourceProvider;
-
 class TestChromeBrowserProvider : public ChromeBrowserProvider {
  public:
   TestChromeBrowserProvider();
@@ -31,11 +29,12 @@ class TestChromeBrowserProvider : public ChromeBrowserProvider {
   UITextField<TextFieldStyling>* CreateStyledTextField(
       CGRect frame) const override NS_RETURNS_RETAINED;
   NSArray* GetAvailableVoiceSearchLanguages() const override;
+  VoiceSearchProvider* GetVoiceSearchProvider() const override;
 
  private:
   std::unique_ptr<ChromeIdentityService> chrome_identity_service_;
-  std::unique_ptr<TestUpdatableResourceProvider>
-      test_updatable_resource_provider_;
+  std::unique_ptr<UpdatableResourceProvider> updatable_resource_provider_;
+  std::unique_ptr<VoiceSearchProvider> voice_search_provider_;
 
   DISALLOW_COPY_AND_ASSIGN(TestChromeBrowserProvider);
 };