android: fix ContentReadbackHandler destroy()

android: fix ContentReadbackHandler destroy()

The native component is not guarranteed to be initialized before destroy()
is called.

BUG=375726
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=272265

[powei, 2014-05-21 17:45:56]

one-line change to fix a crash.  PTAL.  thanks!

[Ted C, 2014-05-21 17:47:11]

lgtm

[powei, 2014-05-21 17:49:22]

The CQ bit was checked by powei@chromium.org

[commit-bot: I haz the power, 2014-05-21 19:58:46]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/powei@chromium.org/295033003/1

[commit-bot: I haz the power, 2014-05-22 12:37:23]

FYI, CQ is re-trying this CL (attempt #1).
Please consider checking whether the failures are real,
and report flakes to chrome-troopers@google.com.
The failing builders are:
  win_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu_triggered...)

[commit-bot: I haz the power, 2014-05-22 12:39:15]

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

[commit-bot: I haz the power, 2014-05-22 12:39:16]

Try jobs failed on following builders:
  win_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu_triggered...)

[powei, 2014-05-22 15:13:08]

The CQ bit was checked by powei@chromium.org

[commit-bot: I haz the power, 2014-05-22 15:15:03]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/powei@chromium.org/295033003/1

[commit-bot: I haz the power, 2014-05-22 15:18:47]

FYI, CQ is re-trying this CL (attempt #1).
Please consider checking whether the failures are real,
and report flakes to chrome-troopers@google.com.
The failing builders are:
  win_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu_triggered...)

[commit-bot: I haz the power, 2014-05-22 15:21:17]

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

[commit-bot: I haz the power, 2014-05-22 15:21:18]

Try jobs failed on following builders:
  win_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu_triggered...)

[powei, 2014-05-22 17:53:09]

The CQ bit was checked by powei@chromium.org

[commit-bot: I haz the power, 2014-05-22 17:53:55]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/powei@chromium.org/295033003/1

[commit-bot: I haz the power, 2014-05-22 19:11:01]

Change committed as 272265