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

content/browser/site_instance_unittest.cc

Index: content/browser/site_instance_unittest.cc
===================================================================
--- content/browser/site_instance_unittest.cc	(revision 105162)
+++ content/browser/site_instance_unittest.cc	(working copy)
@@ -188,7 +188,7 @@
 
   NavigationEntry* e1 = new NavigationEntry(instance, 0, url, GURL(),
                                             string16(),
-                                            PageTransition::LINK);
+                                            content::PAGE_TRANSITION_LINK);
 
   // Redundantly setting e1's SiteInstance shouldn't affect the ref count.
   e1->set_site_instance(instance);
@@ -197,7 +197,7 @@
   // Add a second reference
   NavigationEntry* e2 = new NavigationEntry(instance, 0, url,
                                             GURL(), string16(),
-                                            PageTransition::LINK);
+                                            content::PAGE_TRANSITION_LINK);
 
   // Now delete both entries and be sure the SiteInstance goes away.
   delete e1;
@@ -252,7 +252,7 @@
 
   NavigationEntry* e1 = new NavigationEntry(instance1, 0, url, GURL(),
                                             string16(),
-                                            PageTransition::LINK);
+                                            content::PAGE_TRANSITION_LINK);
   // Clone the entry
   NavigationEntry* e2 = new NavigationEntry(*e1);