Chrome: Crash Report : InstantService::MaybeTranslateInstantPathOnIO

chrome/browser/ui/webui/ntp/thumbnail_source.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 CHROME_BROWSER_UI_WEBUI_NTP_THUMBNAIL_SOURCE_H_
 #define CHROME_BROWSER_UI_WEBUI_NTP_THUMBNAIL_SOURCE_H_
 
+#include <map>
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "content/public/browser/url_data_source.h"
 
 class Profile;
 
 namespace base {
 class RefCountedMemory;
@@ skipping 24 matching lines @@
  private:
   virtual ~ThumbnailSource();
 
   // Raw PNG representation of the thumbnail to show when the thumbnail
   // database doesn't have a thumbnail for a webpage.
   scoped_refptr<base::RefCountedMemory> default_thumbnail_;
 
   // ThumbnailService.
   scoped_refptr<thumbnails::ThumbnailService> thumbnail_service_;
 
-  // Transient copy of the request in play. Valid between
-  // ShouldServiceRequest() and StartDataRequest().
-  mutable const net::URLRequest* current_request_;
+  // Transient mappings from a ID-based path to a URL-based path.

[Dan Beam, 2013/03/20 19:26:13]

an ID-based, an URL-based

[dhollowa, 2013/03/20 19:58:54]

Done.

+  // The key is an ID-string, the value is a URL string.
+  // Mapppings are added in ShouldServiceRequest() and erased once

[Dan Beam, 2013/03/20 19:26:13]

Mappings

[dhollowa, 2013/03/20 19:58:54]

Done.

+  // the request is serviced in StartDataRequest().
+  // TODO(dhollowa): Consider passing the |request| object through
+  // to the |StartDataRequest| call.

[Dan Beam, 2013/03/20 19:26:13]

nit: |StartDataRequest()|

[dhollowa, 2013/03/20 19:58:54]

Done.

+  mutable std::map<std::string, std::string> id_to_url_map_;

[Dan Beam, 2013/03/20 19:26:13]

why does this need to be mutable vs. just making the method non-const?

[dhollowa, 2013/03/20 19:58:54]

Because it is altered in the StartDataRequest() call to clear old mappings.

[dhollowa, 2013/03/20 20:02:08]

I realized I didn't really answer your question here... StartDataRequest() is an
inherited method, so this would require modification for all the data sources. 
And given that id_to_url_map_ is a form of cache, mutable seemed quite
appropriate.

 
   // Only used when servicing requests on the UI thread.
   Profile* const profile_;
 
   DISALLOW_COPY_AND_ASSIGN(ThumbnailSource);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_NTP_THUMBNAIL_SOURCE_H_