Move BrowserThread to content namespace.

TBR=owners
BUG=98716

Review URL: http://codereview.chromium.org/8437002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@108270 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/net/chrome_network_delegate.cc b/chrome/browser/net/chrome_network_delegate.cc
index 21e16d7..a276c61 100644
--- a/chrome/browser/net/chrome_network_delegate.cc
+++ b/chrome/browser/net/chrome_network_delegate.cc
@@ -25,6 +25,8 @@
 #include "chrome/browser/policy/url_blacklist_manager.h"
 #endif
 
+using content::BrowserThread;
+
 namespace {
 
 // If the |request| failed due to problems with a proxy, forward the error to