Switch Extensions::TabHelper to use WebContents, WebContentsUserData.

chrome/browser/ui/views/frame/browser_view.cc

Index: chrome/browser/ui/views/frame/browser_view.cc
diff --git a/chrome/browser/ui/views/frame/browser_view.cc b/chrome/browser/ui/views/frame/browser_view.cc
index 03d0a58d72c3ae1368155316a9e8c9640a4bfa15..1070473cbd1ef027304a7d967d9ed858200da2e4 100644
--- a/chrome/browser/ui/views/frame/browser_view.cc
+++ b/chrome/browser/ui/views/frame/browser_view.cc
@@ -1537,9 +1537,11 @@ bool BrowserView::ShouldShowWindowTitle() const {
 
 gfx::ImageSkia BrowserView::GetWindowAppIcon() {
   if (browser_->is_app()) {
-    TabContents* contents = chrome::GetActiveTabContents(browser_.get());
-    if (contents && contents->extension_tab_helper()->GetExtensionAppIcon())
-      return *contents->extension_tab_helper()->GetExtensionAppIcon();
+    WebContents* contents = chrome::GetActiveWebContents(browser_.get());
+    extensions::TabHelper* extensions_tab_helper =
+        contents ? extensions::TabHelper::FromWebContents(contents) : NULL;
+    if (extensions_tab_helper && extensions_tab_helper->GetExtensionAppIcon())
+      return *extensions_tab_helper->GetExtensionAppIcon();
   }
 
   return GetWindowIcon();