Fix build warning in device_command_screenshot_job.cc

Fix build warning in device_command_screenshot_job.cc

device_command_screenshot_job.cc:132:70: warning: 'result_code' may be used uninitialized in this function [-Wmaybe-uninitialized]

Committed: https://crrev.com/78356a0007b25ab468c34310386537cb24fd19f2
Cr-Commit-Position: refs/heads/master@{#333691}

[dshwang, 2015-06-05 13:16:58]

dongseong.hwang@intel.com changed reviewers:
+ atwilson@chromium.org

[dshwang, 2015-06-05 13:16:58]

atwilson, could you review?

[Andrew T Wilson (Slow), 2015-06-08 16:38:13]

On 2015/06/05 13:16:58, dshwang wrote:
> atwilson, could you review?

Two things:

1) This warning is incorrect, since we are guaranteed that the switch statement
will always initialize result_code. Is there another way to circumvent the
error?

2) Having us ever set the result_code to SUCCESS in an onerror handler seems
wonky. Maybe set it to FAILURE_CLIENT?

[dshwang, 2015-06-09 14:34:29]

On 2015/06/08 16:38:13, Andrew T Wilson wrote:
> On 2015/06/05 13:16:58, dshwang wrote:
> > atwilson, could you review?
> 
> Two things:
> 
> 1) This warning is incorrect, since we are guaranteed that the switch
statement
> will always initialize result_code. Is there another way to circumvent the
> error?

current gcc doesn't care of if the switch statement handles it. we can use
-Wno-uninitialized option to relieve this complaint, but it's unacceptable.

> 
> 2) Having us ever set the result_code to SUCCESS in an onerror handler seems
> wonky. Maybe set it to FAILURE_CLIENT?

got it. Done.

[Andrew T Wilson (Slow), 2015-06-09 18:50:07]

lgtm

[dshwang, 2015-06-10 06:40:13]

The CQ bit was checked by dongseong.hwang@intel.com

[commit-bot: I haz the power, 2015-06-10 06:40:45]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1159163006/20001

[commit-bot: I haz the power, 2015-06-10 06:48:35]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-06-10 06:49:39]

Patchset 2 (id:??) landed as
https://crrev.com/78356a0007b25ab468c34310386537cb24fd19f2
Cr-Commit-Position: refs/heads/master@{#333691}