[ios] Adds a provider API for AudioSessionController.

ios/public/provider/chrome/browser/voice/test_voice_search_provider.h

+// Copyright 2016 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_VOICE_TEST_VOICE_SEARCH_PROVIDER_H_
+#define IOS_PUBLIC_PROVIDER_CHROME_BROWSER_VOICE_TEST_VOICE_SEARCH_PROVIDER_H_
+
+#include <memory>
+
+#include "base/macros.h"
+#include "ios/public/provider/chrome/browser/voice/voice_search_provider.h"
+
+// Test provider that returns dummy values or test objects.
+class TestVoiceSearchProvider : public VoiceSearchProvider {
+ public:
+  TestVoiceSearchProvider();
+  ~TestVoiceSearchProvider() override;
+
+  // VoiceSearchProvider.
+  NSArray* GetAvailableLanguages() const override;
+  AudioSessionController* GetAudioSessionController() const override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TestVoiceSearchProvider);
+};
+
+#endif  // IOS_PUBLIC_PROVIDER_CHROME_BROWSER_VOICE_TEST_VOICE_SEARCH_PROVIDER_H_