Add devtools trace event for event dispatching

Add devtools trace event for event dispatching

Current implementation of InspectorTimelineAgent will emit EventDispatch event only if there is at least one handler on the event's path. After this patch EventDispather::dispatch trace events will be sent for unhandled events too. We should be able to filter out such events later on the front-end side and avoid additional checks at the instrumentation point.

BUG=361045
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=171951

[pfeldman, 2014-04-16 09:01:18]

Lets introduce a test suite that would provide the coverage for
devtools-timeline right away.

https://chromiumcodereview.appspot.com/239303003/diff/60001/Source/core/event...
File Source/core/events/EventDispatcher.cpp (right):

https://chromiumcodereview.appspot.com/239303003/diff/60001/Source/core/event...
Source/core/events/EventDispatcher.cpp:116:
TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("devtools-timeline"),
"EventDispatcher::dispatch", "type",
TRACE_STR_COPY(m_event->type().ascii().data()));
"EventDispatcher::dispatchEvent"

https://chromiumcodereview.appspot.com/239303003/diff/60001/Source/core/event...
Source/core/events/EventDispatcher.cpp:117: // FIXME(361045): remove
InspectorInstrumentation calls once DevTools Timeline migrated on tracing.
migrates to tracing.

[yurys, 2014-04-18 13:38:52]

Added protocol test for the new tracing events.

https://codereview.chromium.org/239303003/diff/60001/Source/core/events/Event...
File Source/core/events/EventDispatcher.cpp (right):

https://codereview.chromium.org/239303003/diff/60001/Source/core/events/Event...
Source/core/events/EventDispatcher.cpp:116:
TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("devtools-timeline"),
"EventDispatcher::dispatch", "type",
TRACE_STR_COPY(m_event->type().ascii().data()));
On 2014/04/16 09:01:19, pfeldman wrote:
> "EventDispatcher::dispatchEvent"

Why? The method is called dispatch. I believe we should use either method name
as the trace event name or front-end name for that event, i.e. non-qualified
"EventDispatch".

https://codereview.chromium.org/239303003/diff/60001/Source/core/events/Event...
Source/core/events/EventDispatcher.cpp:117: // FIXME(361045): remove
InspectorInstrumentation calls once DevTools Timeline migrated on tracing.
On 2014/04/16 09:01:19, pfeldman wrote:
> migrates to tracing.

Done.

[pfeldman, 2014-04-18 13:41:43]

lgtm

[yurys, 2014-04-18 14:47:29]

The CQ bit was checked by yurys@chromium.org

[commit-bot: I haz the power, 2014-04-18 14:47:35]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/yurys@chromium.org/239303003/80001

[commit-bot: I haz the power, 2014-04-18 16:00:33]

Change committed as 171951