Prevents windows that cannot snap from snapping using a keyboard accelerator

BUG=386254
TEST=Open a non-resizable app such as a calculator. Alt+] should not snap it.

Review URL: https://codereview.chromium.org/342823002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@278273 0039d316-1c4b-4281-b951-d872f2087c98

ash/accelerators/accelerator_controller.cc

@@ -509,7 +509,8 @@ bool HandleWindowSnap(int action) {
   // http://crbug.com/135487.
   if (!window_state ||
       window_state->window()->type() != ui::wm::WINDOW_TYPE_NORMAL ||
-      window_state->IsFullscreen()) {
+      window_state->IsFullscreen() ||
+      !window_state->CanSnap()) {
     return false;
   }