DevTools: support configurable category filter for trace events callback

DevTools: support configurable category filter for trace events callback

DevTools callback is currently invoked for all callbacks which is a waste
of time as we only need a few. This will become more critical once we start
processing ConvertableToTraceFormat arguments.
We'd also like to select categories based on the different options enabled,
so let's move the filter to the DevTools back-end.

BUG=

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=254143

[caseq, 2014-02-28 08:46:46]

blink counterpart: https://codereview.chromium.org/184043004/

[pfeldman, 2014-02-28 09:23:01]

lgtm

https://codereview.chromium.org/184283003/diff/1/content/renderer/devtools/de...
File content/renderer/devtools/devtools_agent.h (right):

https://codereview.chromium.org/184283003/diff/1/content/renderer/devtools/de...
content/renderer/devtools/devtools_agent.h:66: virtual void
unsetTraceEventCallback();
reset?

[caseq, 2014-02-28 09:47:57]

The CQ bit was checked by caseq@chromium.org

[commit-bot: I haz the power, 2014-02-28 09:48:08]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/caseq@chromium.org/184283003/20001

[commit-bot: I haz the power, 2014-02-28 16:09:48]

Change committed as 254143