Move BrowserThread to content namespace.

chrome/browser/themes/browser_theme_pack.h

Index: chrome/browser/themes/browser_theme_pack.h
diff --git a/chrome/browser/themes/browser_theme_pack.h b/chrome/browser/themes/browser_theme_pack.h
index e46dc1db51d19add013132e10fe86a8a5a7b72e2..d79fdc48ed51129a181ed0c9dcf2e73f9df1ac6a 100644
--- a/chrome/browser/themes/browser_theme_pack.h
+++ b/chrome/browser/themes/browser_theme_pack.h
@@ -46,7 +46,7 @@ class DictionaryValue;
 // common case, they are backed by mmapped data and the unmmapping operation
 // will trip our IO on the UI thread detector.
 class BrowserThemePack : public base::RefCountedThreadSafe<
-    BrowserThemePack, BrowserThread::DeleteOnFileThread> {
+    BrowserThemePack, content::BrowserThread::DeleteOnFileThread> {
  public:
   // Builds the theme pack from all data from |extension|. This is often done
   // on a separate thread as it takes so long. This can fail and return NULL in
@@ -91,7 +91,8 @@ class BrowserThemePack : public base::RefCountedThreadSafe<
   bool HasCustomImage(int id) const;
 
  private:
-  friend struct BrowserThread::DeleteOnThread<BrowserThread::FILE>;
+  friend struct content::BrowserThread::DeleteOnThread<
+      content::BrowserThread::FILE>;
   friend class DeleteTask<BrowserThemePack>;
   friend class BrowserThemePackTest;