Add Check() to better diagnose www.crbug.com/159941
In icon_loader_mac.mm, if loading image failed, set |image_| to Null.

BUG=159941
Test=None

R=rsesek
TBR=thakis

Review URL: https://chromiumcodereview.appspot.com/11362148

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@167567 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed