Instrumenting CopyData to analyze its slowing down

Instrumenting CopyData to analyze its slowing down
The previous CL moved the copy part from IO thread.
Now, in the worker thread, copying data 15ms on average, instead of the old 5ms in IO thread, which I want to investigate.
I want to separate possible slowness from the task wrapper (what if params are copied in an inefficient way?) from the slowness from the memcpy.

BUG=422489
Committed: https://crrev.com/a0046208af1f285b95809ed9e79a48f8d95a1522
Cr-Commit-Position: refs/heads/master@{#313306}

[vadimt, 2015-01-27 16:20:49]

vadimt@chromium.org changed reviewers:
+ mmenke@chromium.org

[vadimt, 2015-01-27 16:20:50]

mmenke@, please review

[mmenke, 2015-01-27 16:22:19]

On 2015/01/27 16:20:50, vadimt wrote:
> mmenke@, please review

LGTM

[vadimt, 2015-01-27 16:22:35]

The CQ bit was checked by vadimt@chromium.org

[commit-bot: I haz the power, 2015-01-27 16:23:27]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/880973002/1

[commit-bot: I haz the power, 2015-01-27 18:11:23]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-27 18:12:51]

Patchset 1 (id:??) landed as
https://crrev.com/a0046208af1f285b95809ed9e79a48f8d95a1522
Cr-Commit-Position: refs/heads/master@{#313306}