Speculative fix for crash in DOMUIThumbnailSource.

chrome/browser/dom_ui/dom_ui_favicon_source.h

Index: chrome/browser/dom_ui/dom_ui_favicon_source.h
diff --git a/chrome/browser/dom_ui/dom_ui_favicon_source.h b/chrome/browser/dom_ui/dom_ui_favicon_source.h
index 74192880e34d463ab781d37e448a2c2e37da9fd9..08cbddb14b5420b054bc975781337548bd70c00e 100644
--- a/chrome/browser/dom_ui/dom_ui_favicon_source.h
+++ b/chrome/browser/dom_ui/dom_ui_favicon_source.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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.
 
@@ -28,11 +28,7 @@ class DOMUIFavIconSource : public ChromeURLDataManager::DataSource {
                                 bool is_off_the_record,
                                 int request_id);
 
-  virtual std::string GetMimeType(const std::string&) const {
-    // We need to explicitly return a mime type, otherwise if the user tries to
-    // drag the image they get no extension.
-    return "image/png";
-  }
+  virtual std::string GetMimeType(const std::string&) const;
 
   // Called when favicon data is available from the history backend.
   void OnFavIconDataAvailable(FaviconService::Handle request_handle,
@@ -42,7 +38,7 @@ class DOMUIFavIconSource : public ChromeURLDataManager::DataSource {
                               GURL url);
 
  private:
-  virtual ~DOMUIFavIconSource() {}
+  virtual ~DOMUIFavIconSource();
 
   Profile* profile_;
   CancelableRequestConsumerT<int, 0> cancelable_consumer_;