Adding instrumentation to locate the source of jankiness.

Adding instrumentation to locate the source of jankiness.

Previous instrumentations showed that URLRequestResourceBundleJob::GetData
alone is responsible for 20.5 janks per hour in IO thread. I need to instrument
the code inside it to find out which part causes jank.

This is a mechanical change that adds instrumentation required to locate the
source of jankiness (i.e. a long-running fragment of code executed as a part of
the task that causes jank) in the code. See the bug for details on what kind of
jank we are after.
A number of similar CLs were landed, and none of them caused issues. They've
helped to find and fix janky code. The code of the instrumentation is highly
optimized and is not expected to affect performance. The code simply creates a
diagnostic task which is identical to ones created by PostTask or IPC message
handlers. The task gets created only in developer build and in Canary channel.

BUG=422489
Committed: https://crrev.com/d45fc9174cc4fb03eebdcb71d289afc7d1de00b3
Cr-Commit-Position: refs/heads/master@{#302005}

[vadimt, 2014-10-29 23:30:59]

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

[vadimt, 2014-10-29 23:30:59]

kalman@, please provide OWNER's approval

[not at google - send to devlin, 2014-10-29 23:31:42]

lgtm

[not at google - send to devlin, 2014-10-29 23:34:16]

https://codereview.chromium.org/688773002/diff/1/chrome/browser/extensions/ch...
File chrome/browser/extensions/chrome_url_request_util.cc (right):

https://codereview.chromium.org/688773002/diff/1/chrome/browser/extensions/ch...
chrome/browser/extensions/chrome_url_request_util.cc:102:
base::Unretained(read_mime_type)),
(hopefully it's not one of these Binds, in which case you'd need to assign them
to local variables and instrument each separately, but that's likely overkill)

[vadimt, 2014-10-29 23:38:20]

https://codereview.chromium.org/688773002/diff/1/chrome/browser/extensions/ch...
File chrome/browser/extensions/chrome_url_request_util.cc (right):

https://codereview.chromium.org/688773002/diff/1/chrome/browser/extensions/ch...
chrome/browser/extensions/chrome_url_request_util.cc:102:
base::Unretained(read_mime_type)),
On 2014/10/29 23:34:16, kalman wrote:
> (hopefully it's not one of these Binds, in which case you'd need to assign
them
> to local variables and instrument each separately, but that's likely overkill)

Acknowledged.

[vadimt, 2014-10-29 23:38:27]

The CQ bit was checked by vadimt@chromium.org

[commit-bot: I haz the power, 2014-10-29 23:39:57]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/688773002/1

[commit-bot: I haz the power, 2014-10-30 01:13:14]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-10-30 01:14:20]

Patchset 1 (id:??) landed as
https://crrev.com/d45fc9174cc4fb03eebdcb71d289afc7d1de00b3
Cr-Commit-Position: refs/heads/master@{#302005}