[chromedriver] Enable ChromeDriverTest.testSendKeysToElement on Android.

BUG=chromedriver:259
NOTRY=True

Review URL: https://codereview.chromium.org/28923007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229900 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229900
WebPluginDelegateStub::dtor not to call RemoveMappingForNPObjectOwner() is init failed.

AddMappingForNPObjectOwner() won't get called if initialization failed.
Therefore, we should not call RemoveMappingForNPObjectOwner() in dtor in that
case.

BUG=309102,307713
TEST=none

Review URL: https://codereview.chromium.org/29623002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229901 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229901