Make ProfileSyncService a client of memory coordinator

Make ProfileSyncService a client of memory coordinator

When the memory coordinator is enabled, ProfileSyncService becomes a
client of the memory coordinator instead of installing
MemoryPressureListener.

In the implmentation of this CL, both MemoryPressureListener and
MemoryCoordinatorClient are installed regardless of the flag, but as
default MemoryCoordinator is not enabled and when MemoryCoordinator is
enabled by a flag, it is planed to suppress MemoryPressureMonitor
features.

In addition, the current implementation of OnMemoryPressure just
increments a UMA count. OnStateMemoryChange just follows this and
doesn't do any memory reduction.

Design Doc: https://docs.google.com/document/d/1a69mMr7jI7qK0OfKNlrZ350xiXizVMCCe8orGX7K8Uo/edit?ts=57d7968b#

BUG=639700

[hajimehoshi, 2016-10-03 08:48:19]

The CQ bit was checked by hajimehoshi@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-10-03 08:48:29]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[hajimehoshi, 2016-10-03 08:49:53]

Description was changed from

==========
Make ProfileSyncService a client of memory coordinator

When the memory coordinator is enabled, ProfileSyncService becomes a
client of the memory coordinator instead of installing
MemoryPressureListener.

In the implmentation of this CL, both MemoryPressureListener and
MemoryCoordinatorClient are installed regardless of the flag, but as
default MemoryCoordinator is not enabled and when MemoryCoordinator is
enabled by a flag, it is planed to suppress MemoryPressureMonitor
features.

In addition, the current implementation of OnMemoryPressure just
increments a UMA count. OnStateMemoryChange just follows this and
doesn't do any memory reduction.

Design Doc:
https://docs.google.com/document/d/1a69mMr7jI7qK0OfKNlrZ350xiXizVMCCe8orGX7K8...

BUG=639700

BUG=
==========

to

==========
Make ProfileSyncService a client of memory coordinator

When the memory coordinator is enabled, ProfileSyncService becomes a
client of the memory coordinator instead of installing
MemoryPressureListener.

In the implmentation of this CL, both MemoryPressureListener and
MemoryCoordinatorClient are installed regardless of the flag, but as
default MemoryCoordinator is not enabled and when MemoryCoordinator is
enabled by a flag, it is planed to suppress MemoryPressureMonitor
features.

In addition, the current implementation of OnMemoryPressure just
increments a UMA count. OnStateMemoryChange just follows this and
doesn't do any memory reduction.

Design Doc:
https://docs.google.com/document/d/1a69mMr7jI7qK0OfKNlrZ350xiXizVMCCe8orGX7K8...

BUG=639700
==========

[commit-bot: I haz the power, 2016-10-03 08:50:41]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-10-03 08:50:42]

Dry run: Try jobs failed on following builders:
  mac_chromium_compile_dbg_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[hajimehoshi, 2016-10-03 08:50:50]

hajimehoshi@chromium.org changed reviewers:
+ bashi@chromium.org, chrisha@chromium.org, maxbogue@chromium.org

[hajimehoshi, 2016-10-03 09:19:18]

PTAL

[hajimehoshi, 2016-10-03 09:19:28]

The CQ bit was checked by hajimehoshi@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-10-03 09:19:39]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-03 10:04:48]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-10-03 10:04:49]

Dry run: This issue passed the CQ dry run.

[bashi, 2016-10-03 23:26:54]

https://codereview.chromium.org/2385083002/diff/20001/components/browser_sync...
File components/browser_sync/profile_sync_service.cc (right):

https://codereview.chromium.org/2385083002/diff/20001/components/browser_sync...
components/browser_sync/profile_sync_service.cc:2476:
sync_prefs_.GetMemoryPressureWarningCount() + 1);
Do we use the warning count to change behavior of ProfileSyncService or other
classes? In other words, is this purely for calculating statistics? If so,
Making ProfileSyncService be a MCC wouldn't make much sense IMO. Maybe we just
leave this MPL and remove later.

[hajimehoshi, 2016-10-04 05:36:23]

As we discussed offline, let's just remove the UMA. Let me close this.