[Android WebView] Call shouldInterceptRequest on a background thread

android_webview/browser/aw_request_interceptor.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_BROWSER_AW_REQUEST_INTERCEPTOR_H_
-#define ANDROID_WEBVIEW_BROWSER_AW_REQUEST_INTERCEPTOR_H_
-
-#include "base/memory/scoped_ptr.h"
-#include "net/url_request/url_request_interceptor.h"
-
-class GURL;
-
-namespace net {
-class URLRequest;
-class URLRequestContextGetter;
-class URLRequestJob;
-class NetworkDelegate;
-}
-
-namespace android_webview {
-
-class AwWebResourceResponse;
-
-// This class allows the Java-side embedder to substitute the default
-// URLRequest of a given request for an alternative job that will read data
-// from a Java stream.
-class AwRequestInterceptor : public net::URLRequestInterceptor {
- public:
-  AwRequestInterceptor();
-  ~AwRequestInterceptor() override;
-
-  // net::URLRequestInterceptor override --------------------------------------
-  net::URLRequestJob* MaybeInterceptRequest(
-      net::URLRequest* request,
-      net::NetworkDelegate* network_delegate) const override;
-
- private:
-  scoped_ptr<AwWebResourceResponse> QueryForAwWebResourceResponse(
-      net::URLRequest* request) const;
-
-  DISALLOW_COPY_AND_ASSIGN(AwRequestInterceptor);
-};
-
-} // namespace android_webview
-
-#endif  // ANDROID_WEBVIEW_BROWSER_AW_REQUEST_INTERCEPTOR_H_