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

chrome/browser/prerender/prerender_contents.cc

Index: chrome/browser/prerender/prerender_contents.cc
===================================================================
--- chrome/browser/prerender/prerender_contents.cc	(revision 105162)
+++ chrome/browser/prerender/prerender_contents.cc	(working copy)
@@ -319,10 +319,10 @@
   DCHECK(load_start_time_.is_null());
   load_start_time_ = base::TimeTicks::Now();
 
-  PageTransition::Type transition = PageTransition::LINK;
+  content::PageTransition transition = content::PAGE_TRANSITION_LINK;
   if (origin_ == ORIGIN_OMNIBOX_ORIGINAL ||
       origin_ == ORIGIN_OMNIBOX_CONSERVATIVE) {
-    transition = PageTransition::TYPED;
+    transition = content::PAGE_TRANSITION_TYPED;
   }
   new_contents->controller().LoadURL(prerender_url_, referrer_, transition,
                                      std::string());