Fix a crash in Pepper object scripting.

I believe this is caused by a shutdown race condition. My theory is if a pugin
is cread and rapidly destroyed, object creation will fail in the renderer.

TEST=manual
BUG=133581
Review URL: https://chromiumcodereview.appspot.com/10580027

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@143201 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed