Revert 113071 - Revert 113047 - Make ExtensionService use ExtensionSet.

chrome/browser/extensions/extension_webrequest_api.cc

Index: chrome/browser/extensions/extension_webrequest_api.cc
===================================================================
--- chrome/browser/extensions/extension_webrequest_api.cc	(revision 113231)
+++ chrome/browser/extensions/extension_webrequest_api.cc	(working copy)
@@ -1697,9 +1697,9 @@
   bool adblock = false;
   bool adblock_plus = false;
   bool other = false;
-  const ExtensionList* extensions =
+  const ExtensionSet* extensions =
       profile->GetExtensionService()->extensions();
-  for (ExtensionList::const_iterator it = extensions->begin();
+  for (ExtensionSet::const_iterator it = extensions->begin();
        it != extensions->end(); ++it) {
     if (profile->GetExtensionService()->HasUsedWebRequest(*it)) {
       if ((*it)->name().find("Adblock Plus") != std::string::npos) {