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/jankometer.cc b/chrome/browser/jankometer.cc
index 42c7887..a82d87d 100644
--- a/chrome/browser/jankometer.cc
+++ b/chrome/browser/jankometer.cc
@@ -27,6 +27,7 @@
 
 using base::TimeDelta;
 using base::TimeTicks;
+using content::BrowserThread;
 
 namespace {