Correct forward declaration.

TEST=none
BUG=none
Review URL: http://codereview.chromium.org/115873

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@17108 0039d316-1c4b-4281-b951-d872f2087c98

chrome/test/automation/tab_proxy.h

@@ -24,7 +24,9 @@
 class ConstrainedWindowProxy;
 class GURL;
 class Value;
-class IPC::Message;
+namespace IPC {
+class Message;
+};
 
 enum FindInPageDirection { BACK = 0, FWD = 1 };
 enum FindInPageCase { IGNORE_CASE = 0, CASE_SENSITIVE = 1 };