Add method for simulating MemoryPressureListener notifications

Add method for simulating MemoryPressureListener notifications

This patch adds a new static method to MemoryPressureListener which can
be used to simulate memory pressure notifications:

  MemoryPressureListener::SimulatePressureNotification(level);

This patch is a part of the plan to implement a DevTools API for
suppressing and simulating memory pressure signals in Chrome. The main
use case for this feature is to enforce consistent conditions across
memory measurements. See https://goo.gl/cZFdH3 for more details.

BUG=516776
Committed: https://crrev.com/4ab4ed5c5bc25667589866f64d21e1856fefb628
Cr-Commit-Position: refs/heads/master@{#351061}

[petrcermak, 2015-09-25 13:51:45]

Patchset #1 (id:1) has been deleted

[petrcermak, 2015-09-25 13:52:07]

petrcermak@chromium.org changed reviewers:
+ primiano@chromium.org, rmcilroy@chromium.org

[petrcermak, 2015-09-25 13:52:07]

Hi, please review this patch.

Thanks,
Petr

[rmcilroy, 2015-09-25 15:23:39]

lgtm.

https://codereview.chromium.org/1370713002/diff/20001/base/memory/memory_pres...
File base/memory/memory_pressure_listener_unittest.cc (right):

https://codereview.chromium.org/1370713002/diff/20001/base/memory/memory_pres...
base/memory/memory_pressure_listener_unittest.cc:11: using MemoryPressureLevel =
base::MemoryPressureListener::MemoryPressureLevel;
nit - just "using base::MemoryPressureListener::MemoryPressureLevel;" should
work I think.

[petrcermak, 2015-09-25 16:31:04]

+cc chrisha

[petrcermak, 2015-09-25 16:33:24]

Thanks for your comments.

Petr

https://codereview.chromium.org/1370713002/diff/20001/base/memory/memory_pres...
File base/memory/memory_pressure_listener_unittest.cc (right):

https://codereview.chromium.org/1370713002/diff/20001/base/memory/memory_pres...
base/memory/memory_pressure_listener_unittest.cc:11: using MemoryPressureLevel =
base::MemoryPressureListener::MemoryPressureLevel;
On 2015/09/25 15:23:38, rmcilroy wrote:
> nit - just "using base::MemoryPressureListener::MemoryPressureLevel;" should
> work I think.

I had tried it, but it unfortunately doesn't:

../../base/memory/memory_pressure_listener_unittest.cc:11:37: error: using
declaration cannot refer to class member
using base::MemoryPressureListener::MemoryPressureLevel;

[petrcermak, 2015-09-25 16:34:29]

petrcermak@chromium.org changed reviewers:
+ thestig@chromium.org

[petrcermak, 2015-09-25 16:34:29]

thestig@: Hi, could I please get an owner stamp on this patch?

Thanks,
Petr

[chrisha, 2015-09-25 17:03:38]

chrisha@chromium.org changed reviewers:
+ chrisha@chromium.org

[chrisha, 2015-09-25 17:03:39]

lgtm

[Lei Zhang, 2015-09-25 18:00:03]

lgtm

https://codereview.chromium.org/1370713002/diff/20001/base/memory/memory_pres...
File base/memory/memory_pressure_listener_unittest.cc (right):

https://codereview.chromium.org/1370713002/diff/20001/base/memory/memory_pres...
base/memory/memory_pressure_listener_unittest.cc:11: using MemoryPressureLevel =
base::MemoryPressureListener::MemoryPressureLevel;
BTW, you can probably put this within namespace base to save a few letters, if
you had just exceeded 80 cols.

[Primiano Tucci (use gerrit), 2015-09-25 18:06:17]

LGTM % 1 small comment (feel free to ignore)

https://codereview.chromium.org/1370713002/diff/20001/base/memory/memory_pres...
File base/memory/memory_pressure_listener.cc (right):

https://codereview.chromium.org/1370713002/diff/20001/base/memory/memory_pres...
base/memory/memory_pressure_listener.cc:84: void
MemoryPressureListener::DoNotifyMemoryPressure(
looks like this could be a method in the anonymous namespace (no need to expose
it in the .h)

[Lei Zhang, 2015-09-25 18:12:43]

https://codereview.chromium.org/1370713002/diff/20001/base/memory/memory_pres...
File base/memory/memory_pressure_listener.cc (right):

https://codereview.chromium.org/1370713002/diff/20001/base/memory/memory_pres...
base/memory/memory_pressure_listener.cc:84: void
MemoryPressureListener::DoNotifyMemoryPressure(
On 2015/09/25 18:06:17, Primiano Tucci wrote:
> looks like this could be a method in the anonymous namespace (no need to
expose
> it in the .h)

I was going to say that too, but I'm guessing it's referencing Notify() which is
private?

[Primiano Tucci (use gerrit), 2015-09-25 18:16:43]

https://codereview.chromium.org/1370713002/diff/20001/base/memory/memory_pres...
File base/memory/memory_pressure_listener.cc (right):

https://codereview.chromium.org/1370713002/diff/20001/base/memory/memory_pres...
base/memory/memory_pressure_listener.cc:84: void
MemoryPressureListener::DoNotifyMemoryPressure(
On 2015/09/25 18:12:42, Lei Zhang wrote:
> On 2015/09/25 18:06:17, Primiano Tucci wrote:
> > looks like this could be a method in the anonymous namespace (no need to
> expose
> > it in the .h)
> 
> I was going to say that too, but I'm guessing it's referencing Notify() which
is
> private?

Ahh right. nevermind then

[petrcermak, 2015-09-28 09:42:15]

The CQ bit was checked by petrcermak@chromium.org

[commit-bot: I haz the power, 2015-09-28 09:42:35]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1370713002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1370713002/20001

[petrcermak, 2015-09-28 09:42:46]

The CQ bit was unchecked by petrcermak@chromium.org

[petrcermak, 2015-09-28 11:43:29]

Thanks for your comments.

Petr

https://codereview.chromium.org/1370713002/diff/20001/base/memory/memory_pres...
File base/memory/memory_pressure_listener_unittest.cc (right):

https://codereview.chromium.org/1370713002/diff/20001/base/memory/memory_pres...
base/memory/memory_pressure_listener_unittest.cc:11: using MemoryPressureLevel =
base::MemoryPressureListener::MemoryPressureLevel;
On 2015/09/25 18:00:03, Lei Zhang wrote:
> BTW, you can probably put this within namespace base to save a few letters, if
> you had just exceeded 80 cols.

Done.

[petrcermak, 2015-09-28 11:43:35]

The CQ bit was checked by petrcermak@chromium.org

[petrcermak, 2015-09-28 11:43:35]

The patchset sent to the CQ was uploaded after l-g-t-m from
primiano@chromium.org, thestig@chromium.org, chrisha@chromium.org,
rmcilroy@chromium.org
Link to the patchset: https://codereview.chromium.org/1370713002/#ps40001
(title: "Address Lei Zhang's comment")

[commit-bot: I haz the power, 2015-09-28 11:43:44]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1370713002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1370713002/40001

[commit-bot: I haz the power, 2015-09-28 13:05:26]

Committed patchset #2 (id:40001)

[commit-bot: I haz the power, 2015-09-28 13:06:15]

Patchset 2 (id:??) landed as
https://crrev.com/4ab4ed5c5bc25667589866f64d21e1856fefb628
Cr-Commit-Position: refs/heads/master@{#351061}