Don't fail SkMergeImageFilter if one of the inputs are empty

Don't fail SkMergeImageFilter if one of the inputs are empty

If one of the inputs to a SkMergeImageFilter was clipped away or
otherwise caused the filterImage(...) invocation for it to return
false, the entire effect would be "failed" and return false --
regardless of if it had produced a result or not.
Instead of returning false directly if filterImage(...) for a source
returned false, consider all the inputs, and then only return false if
all of them do.

BUG=chromium:489046
Committed: https://skia.googlesource.com/skia/+/d8b57717793f069db2ccd7c8174d0822bd7de6e1

[fs, 2015-05-19 11:52:36]

The CQ bit was checked by fs@opera.com to run a CQ dry run

[commit-bot: I haz the power, 2015-05-19 11:52:45]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1133523006/1

[commit-bot: I haz the power, 2015-05-19 11:52:46]

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 2015-05-19 17:52 UTC

[fs, 2015-05-19 11:53:24]

fs@opera.com changed reviewers:
+ senorblanco@chromium.org

[fs, 2015-05-19 11:54:43]

fs@opera.com changed reviewers:
+ reed@google.com

[reed1, 2015-05-19 12:54:21]

code seems logical, but Stephen should comment on the feature-correctness of the
new behavior.

[reed1, 2015-05-19 12:54:28]

The CQ bit was unchecked by reed@google.com

[Stephen White, 2015-05-19 18:07:17]

LGTM

[fs, 2015-05-20 07:51:58]

The CQ bit was checked by fs@opera.com

[commit-bot: I haz the power, 2015-05-20 07:52:06]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1133523006/1

[commit-bot: I haz the power, 2015-05-20 07:52:24]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/d8b57717793f069db2ccd7c8174d0822bd7de6e1

[bungeman-skia, 2015-05-20 14:07:54]

On 2015/05/20 07:52:24, I haz the power (commit-bot) wrote:
> Committed patchset #1 (id:1) as
> https://skia.googlesource.com/skia/+/d8b57717793f069db2ccd7c8174d0822bd7de6e1

This is causing a layout test failure when rolling into Blink. See

https://storage.googleapis.com/chromium-layout-test-archives/linux_blink_rel/...

I'm currently looking, but is the new result for svg/filters/feMerge.svg more
correct?

[Stephen White, 2015-05-20 14:24:25]

On 2015/05/20 14:07:54, bungeman1 wrote:
> On 2015/05/20 07:52:24, I haz the power (commit-bot) wrote:
> > Committed patchset #1 (id:1) as
> >
https://skia.googlesource.com/skia/+/d8b57717793f069db2ccd7c8174d0822bd7de6e1
> 
> This is causing a layout test failure when rolling into Blink. See
> 
>
https://storage.googleapis.com/chromium-layout-test-archives/linux_blink_rel/...
> 
> I'm currently looking, but is the new result for svg/filters/feMerge.svg more
> correct?

Yes, I think this is a fix for 
https://code.google.com/p/chromium/issues/detail?id=473191

(GPU raster was correct in that case, since it has wider tiles, so the new CPU
result should now match GPU).

[fs, 2015-05-20 14:29:18]

On 2015/05/20 14:24:25, Stephen White wrote:
> On 2015/05/20 14:07:54, bungeman1 wrote:
> > On 2015/05/20 07:52:24, I haz the power (commit-bot) wrote:
> > > Committed patchset #1 (id:1) as
> > >
> https://skia.googlesource.com/skia/+/d8b57717793f069db2ccd7c8174d0822bd7de6e1
> > 
> > This is causing a layout test failure when rolling into Blink. See
> > 
> >
>
https://storage.googleapis.com/chromium-layout-test-archives/linux_blink_rel/...
> > 
> > I'm currently looking, but is the new result for svg/filters/feMerge.svg
more
> > correct?
> 
> Yes, I think this is a fix for 
> https://code.google.com/p/chromium/issues/detail?id=473191
> 
> (GPU raster was correct in that case, since it has wider tiles, so the new CPU
> result should now match GPU).

Yes, that appears to be exactly the same as the bug I was looking at (489046)...
Will dupe or something.

[bungeman-skia, 2015-05-20 14:30:50]

On 2015/05/20 14:29:18, fs wrote:
> On 2015/05/20 14:24:25, Stephen White wrote:
> > On 2015/05/20 14:07:54, bungeman1 wrote:
> > > On 2015/05/20 07:52:24, I haz the power (commit-bot) wrote:
> > > > Committed patchset #1 (id:1) as
> > > >
> >
https://skia.googlesource.com/skia/+/d8b57717793f069db2ccd7c8174d0822bd7de6e1
> > > 
> > > This is causing a layout test failure when rolling into Blink. See
> > > 
> > >
> >
>
https://storage.googleapis.com/chromium-layout-test-archives/linux_blink_rel/...
> > > 
> > > I'm currently looking, but is the new result for svg/filters/feMerge.svg
> more
> > > correct?
> > 
> > Yes, I think this is a fix for 
> > https://code.google.com/p/chromium/issues/detail?id=473191
> > 
> > (GPU raster was correct in that case, since it has wider tiles, so the new
CPU
> > result should now match GPU).
> 
> Yes, that appears to be exactly the same as the bug I was looking at
(489046)...
> Will dupe or something.

Yes, I see now that this restores the expectations prior to
https://codereview.chromium.org/769423008 .
I will rebaseline this one for the Skia roll.

[fs, 2015-05-20 14:32:10]

On 2015/05/20 14:30:50, bungeman1 wrote:
> On 2015/05/20 14:29:18, fs wrote:
> > On 2015/05/20 14:24:25, Stephen White wrote:
> > > On 2015/05/20 14:07:54, bungeman1 wrote:
> > > > On 2015/05/20 07:52:24, I haz the power (commit-bot) wrote:
> > > > > Committed patchset #1 (id:1) as
> > > > >
> > >
> https://skia.googlesource.com/skia/+/d8b57717793f069db2ccd7c8174d0822bd7de6e1
> > > > 
> > > > This is causing a layout test failure when rolling into Blink. See
> > > > 
> > > >
> > >
> >
>
https://storage.googleapis.com/chromium-layout-test-archives/linux_blink_rel/...
> > > > 
> > > > I'm currently looking, but is the new result for svg/filters/feMerge.svg
> > more
> > > > correct?
> > > 
> > > Yes, I think this is a fix for 
> > > https://code.google.com/p/chromium/issues/detail?id=473191
> > > 
> > > (GPU raster was correct in that case, since it has wider tiles, so the new
> CPU
> > > result should now match GPU).
> > 
> > Yes, that appears to be exactly the same as the bug I was looking at
> (489046)...
> > Will dupe or something.
> 
> Yes, I see now that this restores the expectations prior to
> https://codereview.chromium.org/769423008 .
> I will rebaseline this one for the Skia roll.

Great, thanks!