Mac Overlays: Add unittests for CALayerTree

content/common/gpu/ca_layer_tree_mac.mm

 // Copyright 2016 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 "content/common/gpu/ca_layer_tree_mac.h"
 
 #include "base/command_line.h"
 #include "base/mac/sdk_forward_declarations.h"
 #include "base/trace_event/trace_event.h"
 #include "gpu/GLES2/gl2extchromium.h"
@@ skipping 285 matching lines @@
 void CALayerTree::ClipAndSortingLayer::CommitToCA(
     CALayer* superlayer,
     ClipAndSortingLayer* old_layer,
     float scale_factor) {
   bool update_is_clipped = true;
   bool update_clip_rect = true;
   if (old_layer) {
     DCHECK(old_layer->ca_layer);
     std::swap(ca_layer, old_layer->ca_layer);
     update_is_clipped = old_layer->is_clipped != is_clipped;
-    update_clip_rect = old_layer->clip_rect != clip_rect;
+    update_clip_rect = update_is_clipped || old_layer->clip_rect != clip_rect;

[ccameron, 2016/02/17 22:53:33]

Oops, tests discovered a bug.

   } else {
     ca_layer.reset([[CALayer alloc] init]);
     [ca_layer setAnchorPoint:CGPointZero];
     [superlayer addSublayer:ca_layer];
   }
   // Excessive logging to debug white screens (crbug.com/583805).
   // TODO(ccameron): change this back to a DCHECK.
   if ([ca_layer superlayer] != superlayer) {
     LOG(ERROR) << "CALayerTree root layer not attached to tree.";
   }
@@ skipping 129 matching lines @@
     } else {
       // Grey represents a CALayer that has not changed.
       color.reset(CGColorCreateGenericRGB(0, 0, 0, 0.1));
     }
     [ca_layer setBorderWidth:1];
     [ca_layer setBorderColor:color];
   }
 }
 
 }  // namespace content