Added trace events to ResourceDispatcher to try capturing uncategorized time. This is part of an effort to identify what contributes to the ~12.6% "uncategorized" time from the android top 25k experiment.
Since we'll be re-running the experiment with tracing in the future, would like to have tracing events that cover the costlier things that DevTools timeline covers (ResourceReceivedData and ResourceReceiveResponse), as well as some other calls which accounted for ~1% of traces for sites high in "uncategorized" time.
BUG=
Review URL: https://codereview.chromium.org/
26940003
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229596 0039d316-1c4b-4281-b951-d872f2087c98