Plumb pinch virtual viewport flag to CC.

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 58 matching lines @@
 
 // Causes the compositor to render to textures which are then sent to the parent
 // through the texture mailbox mechanism.
 // Requires --enable-compositor-frame-message.
 const char kCompositeToMailbox[] = "composite-to-mailbox";
 
 // Check that property changes during paint do not occur.
 const char kStrictLayerPropertyChangeChecking[] =
     "strict-layer-property-change-checking";
 
+// Virtual viewport for fixed-position elements, scrollbars during pinch.
+const char kEnablePinchVirtualViewport[] = "enable-pinch-virtual-viewport";
+
 const char kEnablePartialSwap[] = "enable-partial-swap";
 // Disable partial swap which is needed for some OpenGL drivers / emulators.
 const char kUIDisablePartialSwap[] = "ui-disable-partial-swap";
 
 const char kEnablePerTilePainting[] = "enable-per-tile-painting";
 const char kUIEnablePerTilePainting[] = "ui-enable-per-tile-painting";
 
 // Renders a border around compositor layers to help debug and study
 // layer compositing.
 const char kShowCompositedLayerBorders[] = "show-composited-layer-borders";
@@ skipping 60 matching lines @@
   return false;
 #elif defined(OS_ANDROID)
   return true;
 #else
   return false;
 #endif
 }
 
 }  // namespace switches
 }  // namespace cc