Revert of cc: Remove WorkerPool class and instead use TaskGraphRunner directly.

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 36 matching lines @@
 
 // The height of the movable top controls.
 const char kTopControlsHeight[] = "top-controls-height";
 
 // Percentage of the top controls need to be hidden before they will auto hide.
 const char kTopControlsHideThreshold[] = "top-controls-hide-threshold";
 
 // Percentage of the top controls need to be shown before they will auto show.
 const char kTopControlsShowThreshold[] = "top-controls-show-threshold";
 
+// Number of worker threads used to rasterize content.
+const char kNumRasterThreads[] = "num-raster-threads";
+
 // Show metrics about overdraw in about:tracing recordings, such as the number
 // of pixels culled, and the number of pixels drawn, for each frame.
 const char kTraceOverdraw[] = "trace-overdraw";
 
 // Re-rasters everything multiple times to simulate a much slower machine.
 // Give a scale factor to cause raster to take that many times longer to
 // complete, such as --slow-down-raster-scale-factor=25.
 const char kSlowDownRasterScaleFactor[] = "slow-down-raster-scale-factor";
 
 // Max tiles allowed for each tilings interest area.
@@ skipping 131 matching lines @@
   if (command_line.HasSwitch(switches::kDisableMapImage))
     return false;
   else if (command_line.HasSwitch(switches::kEnableMapImage))
     return true;
 
   return false;
 }
 
 }  // namespace switches
 }  // namespace cc