Prevents WebURLLoaderMock to crash when didReceiveResponse calls ::cancel().

content/test/weburl_loader_mock.cc

 // Copyright 2013 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 "content/test/weburl_loader_mock.h"
 
 #include "base/logging.h"
 #include "content/test/weburl_loader_mock_factory.h"
 #include "third_party/WebKit/public/platform/WebData.h"
 #include "third_party/WebKit/public/platform/WebURLError.h"
 #include "third_party/WebKit/public/platform/WebURLLoaderClient.h"
 
 WebURLLoaderMock::WebURLLoaderMock(WebURLLoaderMockFactory* factory,
                                    blink::WebURLLoader* default_loader)
     : factory_(factory),
       client_(NULL),
       default_loader_(default_loader),
       using_default_loader_(false),
-      is_deferred_(false) {
+      is_deferred_(false),
+      this_deleted_(NULL) {
 }
 
 WebURLLoaderMock::~WebURLLoaderMock() {
+  // When |this_deleted_| is not null, there is someone interested to know if
+  // |this| got deleted. We notify them by setting the pointed value to true.
+  if (this_deleted_)
+    *this_deleted_ = true;
 }
 
 void WebURLLoaderMock::ServeAsynchronousRequest(
     const blink::WebURLResponse& response,
     const blink::WebData& data,
     const blink::WebURLError& error) {
   DCHECK(!using_default_loader_);
   if (!client_)
     return;
 
+  bool this_deleted = false;
+  this_deleted_ = &this_deleted;
   client_->didReceiveResponse(this, response);
 
+  // didReceiveResponse might end up getting ::cancel() to be called which will
+  // make the ResourceLoader to delete |this|. If that happens, |this_deleted|,
+  // created on the stack, will be set to true.
+  if (this_deleted)
+    return;
+  this_deleted_ = NULL;
+
   if (error.reason) {
     client_->didFail(this, error);
     return;
   }
   client_->didReceiveData(this, data.data(), data.size(), data.size());
   client_->didFinishLoading(this, 0, data.size());
 }
 
 blink::WebURLRequest WebURLLoaderMock::ServeRedirect(
     const blink::WebURLResponse& redirectResponse) {
@@ skipping 44 matching lines @@
 }
 
 void WebURLLoaderMock::setDefersLoading(bool deferred) {
   is_deferred_ = deferred;
   if (using_default_loader_) {
     default_loader_->setDefersLoading(deferred);
     return;
   }
   NOTIMPLEMENTED();
 }