Make the destructor of WebFrameClient virtual.

Make the destructor of WebFrameClient virtual.

Most subclasses of WebFrameClient assume that the destructor of WebFrameClient
is virtual. Currently, CreateChildCounterFrameClient class in WebViewTest.cpp
is in trouble because of this.

BUG=N/A

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=175685

[dshwang, 2014-06-06 15:04:20]

Could you review?

[pfeldman, 2014-06-06 15:14:51]

lgtm

[abarth-chromium, 2014-06-06 16:59:16]

lgtm

[commit-bot: I haz the power, 2014-06-06 16:59:52]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dongseong.hwang@intel.com/320583002/1

[commit-bot: I haz the power, 2014-06-06 18:01:48]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  blink_presubmit on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/blink_presubmit/builds/7174)

[commit-bot: I haz the power, 2014-06-06 18:04:30]

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

[commit-bot: I haz the power, 2014-06-06 18:04:30]

Try jobs failed on following builders:
  blink_presubmit on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/blink_presubmit/builds/7192)

[dshwang, 2014-06-06 18:07:37]

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

[commit-bot: I haz the power, 2014-06-06 18:08:14]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dongseong.hwang@intel.com/320583002/1

[commit-bot: I haz the power, 2014-06-06 18:11:04]

Change committed as 175685