Fix system freeze in accessibility focus ring code.

chrome/browser/chromeos/ui/accessibility_focus_ring_layer.cc

 // Copyright 2014 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.
 
 #include "chrome/browser/chromeos/ui/accessibility_focus_ring_layer.h"
 
 #include "ash/display/display_controller.h"
 #include "ash/shell.h"
 #include "base/bind.h"
 #include "ui/aura/window.h"
@@ skipping 23 matching lines @@
 
   for (int i = 0; i < 36; i++) {
     gfx::Point p = input_ring.points[i];
     gfx::Point prev;
     gfx::Point next;
 
     int prev_index = i;
     do {
       prev_index = (prev_index + 35) % 36;
       prev = input_ring.points[prev_index];
-    } while (prev.x() == p.x() && prev.y() == p.y());
+    } while (prev.x() == p.x() && prev.y() == p.y() && prev_index != i);
 
     int next_index = i;
     do {
       next_index = (next_index + 1) % 36;
       next = input_ring.points[next_index];
-    } while (next.x() == p.x() && next.y() == p.y());
+    } while (next.x() == p.x() && next.y() == p.y() && next_index != i);
 
     gfx::Point delta0 = gfx::Point(sign(p.x() - prev.x()),
                                    sign(p.y() - prev.y()));
     gfx::Point delta1 = gfx::Point(sign(next.x() - p.x()),
                                    sign(next.y() - p.y()));
 
     if (delta0.x() == delta1.x() && delta0.y() == delta1.y()) {
       ring.points[i] = gfx::Point(
           input_ring.points[i].x() + outset * delta0.y(),
           input_ring.points[i].y() - outset * delta0.x());
@@ skipping 62 matching lines @@
     paint.setColor(
         SkColorSetARGBMacro(
             255 * (w - i) * (w - i) / (w * w),
             kFocusRingColorRed, kFocusRingColorGreen, kFocusRingColorBlue));
     path = MakePath(ring_, i, offset);
     canvas->DrawPath(path, paint);
   }
 }
 
 }  // namespace chromeos