fix null-pointer deref in SkComposeShader::toString()

fix null-pointer deref in SkComposeShader::toString()

Committed: https://skia.googlesource.com/skia/+/8464a960b83e3577bfa419693b3b27dfad82c8c8

[hal.canary, 2015-06-16 17:44:11]

halcanary@google.com changed reviewers:
+ robertphillips@google.com

[hal.canary, 2015-06-16 17:44:12]

PTAL

[robertphillips, 2015-06-16 17:46:13]

lgtm + request

https://codereview.chromium.org/1185893007/diff/1/src/core/SkComposeShader.cpp
File src/core/SkComposeShader.cpp (right):

https://codereview.chromium.org/1185893007/diff/1/src/core/SkComposeShader.cp...
src/core/SkComposeShader.cpp:201: str->append("ShaderA: ");
might as well add guards for fShaderA & fShaderB while we're at it.

[hal.canary, 2015-06-16 17:49:31]

On 2015/06/16 17:46:13, robertphillips wrote:
> lgtm + request
> 
> https://codereview.chromium.org/1185893007/diff/1/src/core/SkComposeShader.cpp
> File src/core/SkComposeShader.cpp (right):
> 
>
https://codereview.chromium.org/1185893007/diff/1/src/core/SkComposeShader.cp...
> src/core/SkComposeShader.cpp:201: str->append("ShaderA: ");
> might as well add guards for fShaderA & fShaderB while we're at it.

fShaderA and fShaderB  can't be NULL.

[hal.canary, 2015-06-16 18:47:28]

The CQ bit was checked by halcanary@google.com

[commit-bot: I haz the power, 2015-06-16 18:47:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1185893007/1

[commit-bot: I haz the power, 2015-06-16 18:53:30]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/8464a960b83e3577bfa419693b3b27dfad82c8c8