Move PageTransition into content namespace. While I'm touching all these files, I've also updated...

chrome/browser/extensions/user_script_listener_unittest.cc

Index: chrome/browser/extensions/user_script_listener_unittest.cc
===================================================================
--- chrome/browser/extensions/user_script_listener_unittest.cc	(revision 105162)
+++ chrome/browser/extensions/user_script_listener_unittest.cc	(working copy)
@@ -33,8 +33,9 @@
 ResourceDispatcherHostRequestInfo* CreateRequestInfo(int request_id) {
   return new ResourceDispatcherHostRequestInfo(
       new DummyResourceHandler(), ChildProcessInfo::RENDER_PROCESS, 0, 0, 0,
-      request_id, false, -1, ResourceType::MAIN_FRAME, PageTransition::LINK, 0,
-      false, false, false, content::MockResourceContext::GetInstance());
+      request_id, false, -1, ResourceType::MAIN_FRAME,
+      content::PAGE_TRANSITION_LINK, 0, false, false, false,
+      content::MockResourceContext::GetInstance());
 }
 
 // A simple test net::URLRequestJob. We don't care what it does, only that