Refactoring code so as to avoid possible crash due to null pointer

Refactoring code so as to avoid possible crash due to null pointer

In method InputMethodController::setCompositionFromExistingText we access
the value of baseNode()->isTextNode() without checking whether baseNode is null
or not. This could lead to a possible crash. Now, we have an additional check
for baseNode before accessing baseNode()->isTextNode().

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=190318

[rwlbuis, 2015-02-13 16:27:38]

rob.buis@samsung.com changed reviewers:
+ tkent@chromium.org, yutak@chromium.org

[rwlbuis, 2015-02-13 16:27:38]

Change looks good, but adding some editing reviewers.

[tkent, 2015-02-16 01:34:07]

tkent@chromium.org changed reviewers:
+ yosin@chromium.org
- tkent@chromium.org, yutak@chromium.org

[tkent, 2015-02-16 01:34:07]

-yutak, tkent
+yosin

[Yuta Kitamura, 2015-02-16 10:59:48]

yutak@chromium.org changed reviewers:
+ yutak@chromium.org

[Yuta Kitamura, 2015-02-16 10:59:49]

LGTM, this makes sense.

[Sunil Ratnu, 2015-02-16 12:30:01]

The CQ bit was checked by sunil.ratnu@samsung.com

[commit-bot: I haz the power, 2015-02-16 12:30:35]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/923023002/1

[commit-bot: I haz the power, 2015-02-16 13:21:22]

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

[commit-bot: I haz the power, 2015-02-16 13:21:24]

Try jobs failed on following builders:
  linux_blink_rel on tryserver.blink (JOB_FAILED,
http://build.chromium.org/p/tryserver.blink/builders/linux_blink_rel/builds/4...)

[Sunil Ratnu, 2015-02-16 13:26:06]

The CQ bit was checked by sunil.ratnu@samsung.com

[commit-bot: I haz the power, 2015-02-16 13:26:56]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/923023002/1

[commit-bot: I haz the power, 2015-02-16 14:12:45]

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

[commit-bot: I haz the power, 2015-02-16 14:12:46]

Try jobs failed on following builders:
  linux_blink_rel on tryserver.blink (JOB_FAILED,
http://build.chromium.org/p/tryserver.blink/builders/linux_blink_rel/builds/4...)

[Sunil Ratnu, 2015-02-17 12:31:07]

The CQ bit was checked by sunil.ratnu@samsung.com

[commit-bot: I haz the power, 2015-02-17 12:31:37]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/923023002/1

[commit-bot: I haz the power, 2015-02-17 14:02:50]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=190318