Fix imbalanced keepalive count for event pages when dealing with other views.

BUG=126036
TEST=see bug for repro


Review URL: http://codereview.chromium.org/10310005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@135098 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/extensions/extension_process_manager.h b/chrome/browser/extensions/extension_process_manager.h
index a43e552..adaa7fd14 100644
--- a/chrome/browser/extensions/extension_process_manager.h
+++ b/chrome/browser/extensions/extension_process_manager.h
@@ -194,6 +194,9 @@
   // was not available when the host was first registered.
   void UpdateRegisteredRenderView(content::RenderViewHost* render_view_host);
 
+  // Clears background page data for this extension.
+  void ClearBackgroundPageData(const std::string& extension_id);
+
   BackgroundPageDataMap background_page_data_;
 
   // The time to delay between an extension becoming idle and