SkCanvas::clear() should call down to devices even when the clip is empty.

SkCanvas::clear() should call down to devices even when the clip is empty.

SkDrawIter had a lovely, completely unused, option for this.  Oversight?

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/378e70d8e561b72a904286ea231946f5c8345b9a

[mtklein_C, 2014-11-19 17:23:23]

The CQ bit was checked by mtklein@chromium.org

[commit-bot: I haz the power, 2014-11-19 17:23:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/735233003/1

[commit-bot: I haz the power, 2014-11-19 17:23:49]

Note for Reviewers:
The CQ is waiting for an approval.
If you believe that the CL is not ready yet, or if you would like to L-G-T-M
with comments then please uncheck the CQ checkbox.

Waiting for LGTM from valid reviewer(s) till 2014-11-19 23:23 UTC

[mtklein_C, 2014-11-19 17:28:16]

mtklein@chromium.org changed reviewers:
+ reed@google.com

[commit-bot: I haz the power, 2014-11-19 23:23:48]

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

[commit-bot: I haz the power, 2014-11-19 23:23:50]

No LGTM from a valid reviewer yet. Please ask for an LGTM from a
full Skia committer from
https://skia.googlesource.com/skia/+/master/CQ_COMMITTERS

[reed1, 2014-11-20 16:53:46]

lgtm

[mtklein, 2014-11-20 16:57:02]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2014-11-20 16:57:55]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/735233003/1

[commit-bot: I haz the power, 2014-11-20 16:58:08]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/378e70d8e561b72a904286ea231946f5c8345b9a

[f(malita), 2014-11-21 04:40:53]

On 2014/11/20 16:58:08, I haz the power (commit-bot) wrote:
> Committed patchset #1 (id:1) as
> https://skia.googlesource.com/skia/+/378e70d8e561b72a904286ea231946f5c8345b9a

I think this is causing the Chrome unit_tests failures seen on the roll:
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...

unit_tests unit_tests 
failures:
  PlatformCanvas.SkLayer
  PlatformCanvas.FillLayer

I've isolated the CL by running manual roll tests for the first few revs in a
failing roll (https://chromium.googlesource.com/skia/+log/9176e2c..844aa33):

7cc1a34 - good (https://codereview.chromium.org/744793003/)
0728031 - good (https://codereview.chromium.org/748653002/)
378e70d - bad (https://codereview.chromium.org/725113004/)
cdeeb09 - bad (https://codereview.chromium.org/747783002/)

It's quite possible that the platform canvas unit tests are making some wrong
assumptions and need to be fixed, but since this roll has been stalled for a
while I'm going to revert and buy us time to investigate.

[f(malita), 2014-11-21 04:43:02]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/748733002/ by fmalita@chromium.org.

The reason for reverting is: Chrome unit_tests failures on Mac & Win, blocking
the roll:
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_....