Remove url_constants dependency from tab_contents.h.

chrome/browser/tab_contents/tab_contents.cc

Index: chrome/browser/tab_contents/tab_contents.cc
diff --git a/chrome/browser/tab_contents/tab_contents.cc b/chrome/browser/tab_contents/tab_contents.cc
index 8141c4288f30338513a2cd6002054f1dce31db0c..0f61f442fe5152ba15e88d26e90d916f0e62a61c 100644
--- a/chrome/browser/tab_contents/tab_contents.cc
+++ b/chrome/browser/tab_contents/tab_contents.cc
@@ -410,9 +410,9 @@ void TabContents::RegisterUserPrefs(PrefService* prefs) {
                                      IDS_STATIC_ENCODING_LIST);
 }
 
-bool TabContents::SupportsURL(GURL* url) {
-  // TODO(brettw) remove this function.
-  return true;
+// Returns true if contains content rendered by an extension.
+bool TabContents::HostsExtension() const {
+  return GetURL().SchemeIs(chrome::kExtensionScheme);
 }
 
 AutofillManager* TabContents::GetAutofillManager() {