This fixes an InvalidRead error that valgrind found....

chrome/browser/tab_contents/thumbnail_generator.cc

 // Copyright (c) 2009 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/tab_contents/thumbnail_generator.h"
 
 #include <algorithm>
 #include <map>
 
 #include "base/histogram.h"
@@ skipping 375 matching lines @@
 }
 
 void ThumbnailGenerator::TabContentsDisconnected(TabContents* contents) {
   // Go through the existing callbacks, and find any that have the
   // same renderer as this TabContents and remove them so they don't
   // hang around.
   ThumbnailCallbackMap::iterator iterator = callback_map_.begin();
   RenderWidgetHost* renderer = contents->render_view_host();
   while (iterator != callback_map_.end()) {
     if (iterator->second->renderer == renderer) {
-      callback_map_.erase(iterator);
+      ThumbnailCallbackMap::iterator nuked = iterator;
+      ++iterator;
+      callback_map_.erase(nuked);
+      continue;
     }
     ++iterator;
   }
 }
 
 void ThumbnailGenerator::ShownDelayHandler() {
   base::TimeTicks threshold = base::TimeTicks::Now() -
       base::TimeDelta::FromMilliseconds(kVisibilitySlopMS);
 
   // Check the list of all pending RWHs (normally only one) to see if any of
@@ skipping 17 matching lines @@
                  &ThumbnailGenerator::ShownDelayHandler);
   }
 }
 
 void ThumbnailGenerator::EraseHostFromShownList(RenderWidgetHost* widget) {
   std::vector<RenderWidgetHost*>::iterator found =
       std::find(shown_hosts_.begin(), shown_hosts_.end(), widget);
   if (found != shown_hosts_.end())
     shown_hosts_.erase(found);
 }