Add a flag for enabling compositor property trees

cc/base/switches.cc

 // Copyright (c) 2012 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 "cc/base/switches.h"
 
 #include "base/command_line.h"
 
 namespace cc {
 namespace switches {
@@ skipping 38 matching lines @@
 // computed by CalcDrawProperties.
 const char kEnablePropertyTreeVerification[] =
     "enable-property-tree-verification";
 
 // Use a BeginFrame signal from browser to renderer to schedule rendering.
 const char kEnableBeginFrameScheduling[] = "enable-begin-frame-scheduling";
 
 // Enables the GPU benchmarking extension
 const char kEnableGpuBenchmarking[] = "enable-gpu-benchmarking";
 
+// Enables the use of property trees rather than CalcDrawProps for computing
+// draw properties.
+const char kEnableCompositorPropertyTrees[] =
+    "enable-compositor-property-trees";
+
 // Renders a border around compositor layers to help debug and study
 // layer compositing.
 const char kShowCompositedLayerBorders[] = "show-composited-layer-borders";
 const char kUIShowCompositedLayerBorders[] = "ui-show-layer-borders";
 
 // Draws a heads-up-display showing Frames Per Second as well as GPU memory
 // usage. If you also use --vmodule="head*=1" then FPS will also be output to
 // the console log.
 const char kShowFPSCounter[] = "show-fps-counter";
 const char kUIShowFPSCounter[] = "ui-show-fps-counter";
@@ skipping 23 matching lines @@
     "ui-show-replica-screenspace-rects";
 
 // Prevents the layer tree unit tests from timing out.
 const char kCCLayerTreeTestNoTimeout[] = "cc-layer-tree-test-no-timeout";
 
 // Makes pixel tests write their output instead of read it.
 const char kCCRebaselinePixeltests[] = "cc-rebaseline-pixeltests";
 
 }  // namespace switches
 }  // namespace cc