[Android WebView] Call shouldInterceptRequest on a background thread

android_webview/browser/aw_request_handler.cc

+// Copyright 2015 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.
+
+#include "android_webview/browser/aw_request_handler.h"
+
+#include "android_webview/browser/aw_contents_io_thread_client.h"
+#include "android_webview/browser/aw_web_resource_response.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/resource_request_info.h"
+#include "net/url_request/url_request.h"
+#include "net/url_request/url_request_job.h"
+
+namespace android_webview {
+
+AwRequestHandler::AwRequestHandler() {
+}
+
+AwRequestHandler::~AwRequestHandler() {
+}
+
+AndroidStreamReaderURLRequestJob* AwRequestHandler::MaybeInterceptRequest(
+    net::URLRequest* request,
+    net::NetworkDelegate* network_delegate) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+  if (job_.get()) return nullptr;

[boliu, 2015/09/28 23:26:28]

This probably deserves a comment. I think this is meant to be "only create job
once per request", but casual reader is going to wonder why return null when you
already have a job here.

[mnaganov (inactive), 2015/09/29 00:14:06]

Done.

+
+  if (!QueryForAwWebResourceResponse(request))
+    return nullptr;
+  job_ = new AndroidStreamReaderURLRequestJob(request, network_delegate);
+  return job_.get();
+}
+
+bool AwRequestHandler::QueryForAwWebResourceResponse(net::URLRequest* request) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+
+  int render_process_id, render_frame_id;
+  if (!content::ResourceRequestInfo::GetRenderFrameForRequest(
+          request, &render_process_id, &render_frame_id)) {
+    return false;
+  }
+
+  scoped_ptr<AwContentsIoThreadClient> io_thread_client =
+      AwContentsIoThreadClient::FromID(render_process_id, render_frame_id);
+
+  if (!io_thread_client.get())
+    return false;
+
+  GURL referrer(request->referrer());
+  if (referrer.is_valid() &&
+      (!request->is_pending() || request->is_redirecting())) {
+    request->SetExtraRequestHeaderByName(net::HttpRequestHeaders::kReferer,
+                                         referrer.spec(), true);
+  }
+  io_thread_client->ShouldInterceptRequestAsync(
+      request,
+      base::Bind(&AwRequestHandler::QueryForAwWebResourceResponseDone, this));
+  return true;
+}
+
+void AwRequestHandler::QueryForAwWebResourceResponseDone(
+    scoped_ptr<AwWebResourceResponse> response) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+  if (!job_.get()) return;
+
+  if (response) {
+    // The job will own the AwWebResourceResponse.
+    AwWebResourceResponse::JobDeliverResponseFromEmbedder(job_.get(),
+                                                          response.Pass());
+  } else {
+    job_->DeliverResponseFromNetwork();
+  }
+}
+
+}  // namespace android_webview