Remove base/platform_thread.h stub and fix up all callers to use the new location and namespace.

TEST=none
BUG=none

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@70346 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome_frame/metrics_service.h b/chrome_frame/metrics_service.h
index 5976c18..46f39ed9 100644
--- a/chrome_frame/metrics_service.h
+++ b/chrome_frame/metrics_service.h
@@ -15,8 +15,8 @@
 #include "base/lazy_instance.h"
 #include "base/lock.h"
 #include "base/metrics/histogram.h"
-#include "base/platform_thread.h"
 #include "base/scoped_ptr.h"
+#include "base/threading/platform_thread.h"
 #include "base/threading/thread_local.h"
 #include "chrome/common/metrics_helpers.h"
 
@@ -139,7 +139,7 @@
   // A number that identifies the how many times the app has been launched.
   int session_id_;
 
-  PlatformThreadId thread_;
+  base::PlatformThreadId thread_;
 
   // Indicates if this is the first uma upload from this instance.
   bool initial_uma_upload_;