Make URLDataSource::GetSource() const.

chrome/browser/ui/webui/session_favicon_source.cc

 // 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.
 
 #include "chrome/browser/ui/webui/session_favicon_source.h"
 
 #include "chrome/browser/sync/glue/session_model_associator.h"
 #include "chrome/browser/sync/profile_sync_service_factory.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/common/url_constants.h"
 
 using browser_sync::SessionModelAssociator;
 
 SessionFaviconSource::SessionFaviconSource(Profile* profile)
     : FaviconSource(profile, FaviconSource::FAVICON) {
 }
 
 SessionFaviconSource::~SessionFaviconSource() {
 }
 
-std::string SessionFaviconSource::GetSource() {
+std::string SessionFaviconSource::GetSource() const {
   return chrome::kChromeUISessionFaviconHost;
 }
 
 std::string SessionFaviconSource::GetMimeType(const std::string&) const {
   return "image/png";
 }
 
 bool SessionFaviconSource::ShouldReplaceExistingSource() const {
   // Leave the existing DataSource in place, otherwise we'll drop any pending
   // requests on the floor.
@@ skipping 14 matching lines @@
 
   scoped_refptr<base::RefCountedMemory> response;
   if (associator &&
       associator->GetSyncedFaviconForPageURL(request.request_path,
                                              &response)) {
     request.callback.Run(response);
     return true;
   }
   return false;
 }