Add CaretBase::m_caretPainter, and compute caretBrowsing lazily.

Add CaretBase::m_caretPainter, and compute caretBrowsing lazily.

This avoids redundant computation of which LayoutBlock is responsible for
painting the caret.

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=198425

[jbroman, 2015-07-07 15:20:54]

jbroman@chromium.org changed reviewers:
+ pdr@chromium.org

[jbroman, 2015-07-07 15:20:55]

2.3 - 2.4% win instead of 3%, but substantially simpler. Good thinking.

https://storage.cloud.google.com/cluster-telemetry/tasks/chromium_perf_runs/j...

This CL replaces https://codereview.chromium.org/1218013003/.

[pdr., 2015-07-07 20:54:53]

On 2015/07/07 at 15:20:55, jbroman wrote:
> 2.3 - 2.4% win instead of 3%, but substantially simpler. Good thinking.
> 
>
https://storage.cloud.google.com/cluster-telemetry/tasks/chromium_perf_runs/j...
> 
> This CL replaces https://codereview.chromium.org/1218013003/.

LGTM

[jbroman, 2015-07-07 20:57:18]

The CQ bit was checked by jbroman@chromium.org

[commit-bot: I haz the power, 2015-07-07 20:57:35]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1226833007/1

[commit-bot: I haz the power, 2015-07-07 21:02:23]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=198425