Switch SnapshotTabHelper to use WebContentsUserData.

chrome/browser/ui/tab_contents/tab_contents.h

Index: chrome/browser/ui/tab_contents/tab_contents.h
diff --git a/chrome/browser/ui/tab_contents/tab_contents.h b/chrome/browser/ui/tab_contents/tab_contents.h
index b66e0aa5c6837e6814acfc9986881d2581f8dfed..67a9a1da8e73a7625365265dc14dcb26ad6c5144 100644
--- a/chrome/browser/ui/tab_contents/tab_contents.h
+++ b/chrome/browser/ui/tab_contents/tab_contents.h
@@ -53,7 +53,6 @@ class Profile;
 class SadTabHelper;
 class SearchEngineTabHelper;
 class ShellWindow;
-class SnapshotTabHelper;
 class TabAutofillManagerDelegate;
 class TabContentsSSLHelper;
 class TabContentsTestHarness;
@@ -270,10 +269,6 @@ class TabContents : public content::WebContentsObserver {
     return search_tab_helper_.get();
   }
 
-  SnapshotTabHelper* snapshot_tab_helper() {
-    return snapshot_tab_helper_.get();
-  }
-
   TabContentsSSLHelper* ssl_helper() { return ssl_helper_.get(); }
 
   browser_sync::SyncedTabDelegate* synced_tab_delegate() {
@@ -355,7 +350,6 @@ class TabContents : public content::WebContentsObserver {
   scoped_ptr<SadTabHelper> sad_tab_helper_;
   scoped_ptr<SearchEngineTabHelper> search_engine_tab_helper_;
   scoped_ptr<chrome::search::SearchTabHelper> search_tab_helper_;
-  scoped_ptr<SnapshotTabHelper> snapshot_tab_helper_;
   scoped_ptr<TabContentsSSLHelper> ssl_helper_;
   scoped_ptr<browser_sync::SyncedTabDelegate> synced_tab_delegate_;