clarify description for force_software_readback_from_2d_canvas

gpu/config/gpu_driver_bug_list_json.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Determines whether a certain driver bug exists in the current system.
 // The format of a valid gpu_driver_bug_list.json file is defined in
 // <gpu/config/gpu_control_list_format.txt>.
 // The supported "features" can be found in
 // <gpu/config/gpu_driver_bug_workaround_type.h>.
 
@@ skipping 2194 matching lines @@
         "op": "=",
         "value": "3.3"
       },
       "features": [
         "remove_invariant_and_centroid_for_essl3"
       ]
     },
     {
       "id": 204,
       "cr_bugs": [665656],
-      "description": "Hardware readback from 2D canvas flaky on Mac Intel",
+      "description": "Hardware readback from 2D canvas to WebGL texture is flaky on Mac Intel",
       "os": {
         "type": "macosx"
       },
       "vendor_id": "0x8086",
       "features": [
         "force_software_readback_from_2d_canvas"
       ]
     }
   ]
   // Please update the version number at beginning of this file whenever you
   // change this file.
 }
 
 );  // LONG_STRING_CONST macro
 
 }  // namespace gpu