[DevTools] Use WebLayerTreeView::layerTreeId() for instrumentation.

[DevTools] Use WebLayerTreeView::layerTreeId() for instrumentation.

Instead of pushing layer tree id from content, we pull it via WebLayerTreeView. This ensures we can update it exactly when it's changed, and allows to instrument cross-process subframes.

BUG=480980
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=194438

[dgozman, 2015-04-24 14:11:34]

dgozman@chromium.org changed reviewers:
+ caseq@chromium.org, kenrb@chromium.org, pfeldman@chromium.org

[dgozman, 2015-04-24 14:11:35]

Could you please take a look?

Added method implemented in https://codereview.chromium.org/1097353004/.

[kenrb, 2015-04-24 15:12:41]

Why does this need to get updated like this for child frames but not for main
frames (i.e. via WebViewImpl)?

[dgozman, 2015-04-24 16:48:50]

On 2015/04/24 15:12:41, kenrb wrote:
> Why does this need to get updated like this for child frames but not for main
> frames (i.e. via WebViewImpl)?

But it is updated for main frame in WebViewImpl.cpp.

[pfeldman, 2015-04-24 16:59:31]

lgtm

[kenrb, 2015-04-24 17:06:44]

On 2015/04/24 16:48:50, dgozman wrote:
> On 2015/04/24 15:12:41, kenrb wrote:
> > Why does this need to get updated like this for child frames but not for
main
> > frames (i.e. via WebViewImpl)?
> 
> But it is updated for main frame in WebViewImpl.cpp.

Sorry, I somehow missed that the first time through.

lgtm

[dgozman, 2015-04-25 06:45:46]

The CQ bit was checked by dgozman@chromium.org

[commit-bot: I haz the power, 2015-04-25 06:46:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1102933002/1

[commit-bot: I haz the power, 2015-04-25 16:41:41]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=194438