Trace frame_time for SendBeginFrame

Trace frame_time for SendBeginFrame

It is useful for linking the BeginFrame sent from browser side and
the BeginFrame received in renderer side. Often, the BeginFrame IPC
message gets delayed and it becomes hard to track the BeginFrame
received in renderer side is from which browser VSync. By dumping the
frame_time, we can then do the cross-reference.

BUG=406112
TEST=RenderWidgetHostViewAndroid::SendBeginFrame now shows frame_time.

Committed: https://crrev.com/77ca6c1d24d114ab5d595bed0a14aa3ecdacac33
Cr-Commit-Position: refs/heads/master@{#294260}

[Yufeng Shen (Slow to review), 2014-09-10 21:53:40]

miletus@chromium.org changed reviewers:
+ sievers@chromium.org, skyostil@chromium.org

[no sievers, 2014-09-10 22:02:31]

lgtm

[Yufeng Shen (Slow to review), 2014-09-10 22:03:41]

The CQ bit was checked by miletus@chromium.org

[commit-bot: I haz the power, 2014-09-10 22:04:19]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/miletus@chromium.org/561883003/1

[commit-bot: I haz the power, 2014-09-10 23:43:15]

Committed patchset #1 (id:1) as 593bfbe2b6022e1da4a41544493f8000afc693dc

[commit-bot: I haz the power, 2014-09-10 23:53:24]

Patchset 1 (id:??) landed as
https://crrev.com/77ca6c1d24d114ab5d595bed0a14aa3ecdacac33
Cr-Commit-Position: refs/heads/master@{#294260}