[Android WebView] Call shouldInterceptRequest on a background thread

android_webview/native/aw_contents_io_thread_client_impl.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_AW_CONTENTS_IO_THREAD_CLIENT_IMPL_H_
 #define ANDROID_WEBVIEW_NATIVE_AW_CONTENTS_IO_THREAD_CLIENT_IMPL_H_
 
 #include "android_webview/browser/aw_contents_io_thread_client.h"
 
 #include "base/android/scoped_java_ref.h"
@@ skipping 29 matching lines @@
 
   // Either |pending_associate| is true or |jclient| holds a non-null
   // Java object.
   AwContentsIoThreadClientImpl(bool pending_associate,
                                const base::android::JavaRef<jobject>& jclient);
   ~AwContentsIoThreadClientImpl() override;
 
   // Implementation of AwContentsIoThreadClient.
   bool PendingAssociation() const override;
   CacheMode GetCacheMode() const override;
-  scoped_ptr<AwWebResourceResponse> ShouldInterceptRequest(
-      const net::URLRequest* request) override;
+  void ShouldInterceptRequestAsync(
+      const net::URLRequest* request,
+      const ShouldInterceptRequestResultCallback callback) override;
   bool ShouldBlockContentUrls() const override;
   bool ShouldBlockFileUrls() const override;
   bool ShouldAcceptThirdPartyCookies() const override;
   bool ShouldBlockNetworkLoads() const override;
   void NewDownload(const GURL& url,
                    const std::string& user_agent,
                    const std::string& content_disposition,
                    const std::string& mime_type,
                    int64 content_length) override;
   void NewLoginRequest(const std::string& realm,
                        const std::string& account,
                        const std::string& args) override;
   void OnReceivedError(const net::URLRequest* request) override;
   void OnReceivedHttpError(
       const net::URLRequest* request,
       const net::HttpResponseHeaders* response_headers) override;
 
  private:
   bool pending_association_;
   base::android::ScopedJavaGlobalRef<jobject> java_object_;
+  base::android::ScopedJavaGlobalRef<jobject> bg_thread_client_object_;

[boliu, 2015/10/01 19:13:56]

Sorry.. just noticed this will prevent AwContents from gc-ed. But I guess it's
ok since this is short-lived, only during the duration of the callback.

Just to be safe, maybe code the java class to only hold a reference to
mContentClient instead of all of AwContents?

Definitely worth a comment though, either way.

[mnaganov (inactive), 2015/10/01 19:51:04]

The lifetime and properties of BackgroundThreadClientImpl are absolutely the
same as of IoThreadClientImpl. We already hold a reference to IoThreadClientImpl
Java object here, so adding a reference to BackgroundThreadClientImpl doesn't
hurt.

I agree with your note about only holding mContentsClient rather than full
AwContents, but let's make that in another CL.

 
   DISALLOW_COPY_AND_ASSIGN(AwContentsIoThreadClientImpl);
 };
 
 // JNI registration method.
 bool RegisterAwContentsIoThreadClientImpl(JNIEnv* env);
 
 } // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_NATIVE_AW_CONTENTS_IO_THREAD_CLIENT_IMPL_H_