Revert 221427 "Add instrumentation to the MessagePumpMac family ..."

Revert 221427 "Add instrumentation to the MessagePumpMac family ..."

This code is no longer needed, since the experiment is not viable.

> Add instrumentation to the MessagePumpMac family of classes.
>
> This adds UMA-uploaded histograms of sampling intervals for key points of data:
> * Total time spent in a CFRunLoop
> * Total time waiting in CFRunLoop
> * Total time servicing MessagePump::Delegate (the MessageLoop)
> * The MessageLoop queue size and queueing delay before servicing
>
> It adds 1 second sampling for 15 seconds at startup, only for the main thread
> (NSApplication-based) run loops.
>
> The data will be used to determine if adding scheduling-like behavior to the
> MessagePump will result in more efficient processing of the MessageLoop work.
>
> An unforunate side effect of this change is exposing another method on the
> MessagePump::Delegate interface, but there does not appear to be a better way
> to do this.
>
> BUG=264886
> R=jar@chromium.org, mark@chromium.org
>
> Review URL: https://codereview.chromium.org/22911026

TBR=rsesek@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=280939

[Robert Sesek, 2014-07-01 21:44:14]

The CQ bit was checked by rsesek@chromium.org

[commit-bot: I haz the power, 2014-07-01 21:44:56]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/rsesek@chromium.org/360373004/1

[commit-bot: I haz the power, 2014-07-02 02:04:01]

Change committed as 280939

[tzik, 2014-07-02 03:29:41]

A revert of this CL has been created in
https://codereview.chromium.org/366873002/ by tzik@chromium.org.

The reason for reverting is: This revert seems to cause build failure:

http://build.chromium.org/p/chromium.memory/builders/Linux%20ASan%20LSan%20Bu...
http://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%2...
http://build.chromium.org/p/chromium.linux/builders/Linux%20Builder/builds/34221
.