WebView: Cleanup class/struct forward declarations

android_webview/native/android_protocol_handler.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 ANDROID_WEBVIEW_NATIVE_ANDROID_PROTOCOL_HANDLER_H_
 #define ANDROID_WEBVIEW_NATIVE_ANDROID_PROTOCOL_HANDLER_H_
 
 #include <memory>
 
 #include "base/android/jni_android.h"
 
 namespace net {
-class URLRequestContext;
 class URLRequestInterceptor;
 }  // namespace net
 
 namespace android_webview {
 
 // These methods create interceptors for Android WebView-specific schemes:
 //
 //  - "content:" scheme is used for accessing data from Android content
 //    providers, see http://developer.android.com/guide/topics/providers/
 //      content-provider-basics.html#ContentURIs
 std::unique_ptr<net::URLRequestInterceptor>
 CreateContentSchemeRequestInterceptor();
 
 //  - "file:" scheme extension for accessing application assets and resources
 //    (file:///android_asset/ and file:///android_res/), see
 //    http://developer.android.com/reference/android/webkit/
 //      WebSettings.html#setAllowFileAccess(boolean)
 std::unique_ptr<net::URLRequestInterceptor> CreateAssetFileRequestInterceptor();
 
 bool RegisterAndroidProtocolHandler(JNIEnv* env);
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_NATIVE_ANDROID_PROTOCOL_HANDLER_H_