Add a command-line switch --enable-per-tile-painting.

content/public/common/content_switches.cc

 // Copyright (c) 2011 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/public/common/content_switches.h"
 
 namespace switches {
 
 // By default, file:// URIs cannot read other file:// URIs. This is an
 // override for developers who need the old behavior for testing.
@@ skipping 537 matching lines @@
 // Use the system SSL library (Secure Transport on Mac, SChannel on Windows)
 // instead of NSS for SSL.
 const char kUseSystemSSL[]                  = "use-system-ssl";
 #endif
 
 #if !defined(OFFICIAL_BUILD)
 // Causes the renderer process to throw an assertion on launch.
 const char kRendererCheckFalseTest[]        = "renderer-check-false-test";
 #endif
 
+// Enable per-tile page drawing.
+// Please note that this flag is honored only if chromium is compiled with
+// SKIA_GPU flag, which can be enabled by setting use_skia_gpu variable to 1
+// in build/features_override.gypi.
+const char kEnablePerTileDrawing[]          = "enable-per-tile-drawing";
+
 }  // namespace switches