Following example of BrowserRenderProcessHost::OnMessageReceived, respond to sync messages even if router failed to route.
Following example of BrowserRenderProcessHost::OnMessageReceived, respond to sync messages even if router failed to route.

BUG=none
TEST=remove a route in a debugger and see what happens

Review URL: http://codereview.chromium.org/6574008

git-svn-id: http://src.chromium.org/svn/trunk/src@75828 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: cbd4d6f30722bdf4d71a6411380e80be6bc125d2
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser