Revert of Remove the acclerated overflow scroll and fixed root background flags.

content/public/common/content_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 "content/public/common/content_switches.h"
 
 #include "base/command_line.h"
 
 namespace switches {
 
@@ skipping 63 matching lines @@
 
 // Disables client-visible 3D APIs, in particular WebGL and Pepper 3D.
 // This is controlled by policy and is kept separate from the other
 // enable/disable switches to avoid accidentally regressing the policy
 // support for controlling access to these APIs.
 const char kDisable3DAPIs[]                 = "disable-3d-apis";
 
 // Disable gpu-accelerated 2d canvas.
 const char kDisableAccelerated2dCanvas[]    = "disable-accelerated-2d-canvas";
 
+// Disables accelerated compositing for backgrounds of root layers with
+// background-attachment: fixed.
+const char kDisableAcceleratedFixedRootBackground[] =
+    "disable-accelerated-fixed-root-background";
+
+// Disables accelerated compositing for overflow scroll.
+const char kDisableAcceleratedOverflowScroll[] =
+    "disable-accelerated-overflow-scroll";
+
 // Disables layer squashing.
 const char kDisableLayerSquashing[] =
     "disable-layer-squashing";
 
 // Disables hardware acceleration of video decode, where available.
 const char kDisableAcceleratedVideoDecode[] =
     "disable-accelerated-video-decode";
 
 // Disable the ApplicationCache.
 const char kDisableApplicationCache[]       = "disable-application-cache";
@@ skipping 173 matching lines @@
 
 // Enable bleeding-edge code to make Chrome draw content faster. The changes
 // behind this path are very likely to break lots of content.
 // ** DO NOT use this flag unless you know what you are doing. **
 const char kEnableBleedingEdgeRenderingFastPaths[] =
     "enable-bleeding-edge-rendering-fast-paths";
 
 // Disable deferred image filters.
 const char kDisableDeferredFilters[]         = "disable-deferred-filters";
 
+// Enables accelerated compositing for backgrounds of root layers with
+// background-attachment: fixed.
+const char kEnableAcceleratedFixedRootBackground[] =
+    "enable-accelerated-fixed-root-background";
+
+// Enables accelerated compositing for overflow scroll. Promotes eligible
+// overflow:scroll elements to layers to enable accelerated scrolling for them.
+const char kEnableAcceleratedOverflowScroll[] =
+    "enable-accelerated-overflow-scroll";
+
 // Enables LCD text.
 const char kEnableLCDText[]                 = "enable-lcd-text";
 
 // Enables using signed distance fields when rendering text.
 // Only valid if GPU rasterization is enabled as well.
 const char kEnableDistanceFieldText[]       = "enable-distance-field-text";
 
 // Enables experimental feature that maps multiple RenderLayers to
 // one composited layer to avoid pathological layer counts.
 const char kEnableLayerSquashing[] =
@@ skipping 621 matching lines @@
 // Enable the Win32K process mitigation policy for renderer processes which
 // prevents them from invoking user32 and gdi32 system calls which enter
 // the kernel. This is only supported on Windows 8 and beyond.
 const char kEnableWin32kRendererLockDown[]
     = "enable_win32k_renderer_lockdown";
 #endif
 
 // Don't dump stuff here, follow the same order as the header.
 
 }  // namespace switches