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

content/renderer/render_view_impl.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/renderer/render_view_impl.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "base/auto_reset.h"
@@ skipping 390 matching lines @@
 
 static bool PreferCompositingToLCDText(float device_scale_factor) {
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
   if (command_line.HasSwitch(switches::kDisablePreferCompositingToLCDText))
     return false;
   if (command_line.HasSwitch(switches::kEnablePreferCompositingToLCDText))
     return true;
   return DeviceScaleEnsuresTextQuality(device_scale_factor);
 }
 
+static bool ShouldUseAcceleratedCompositingForOverflowScroll(
+    float device_scale_factor) {
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+
+  if (command_line.HasSwitch(switches::kDisableAcceleratedOverflowScroll))
+    return false;
+
+  if (command_line.HasSwitch(switches::kEnableAcceleratedOverflowScroll))
+    return true;
+
+  return DeviceScaleEnsuresTextQuality(device_scale_factor);
+}
+
 static bool ShouldUseCompositedScrollingForFrames(
     float device_scale_factor) {
   if (RenderThreadImpl::current() &&
       !RenderThreadImpl::current()->is_lcd_text_enabled())
     return true;
 
   return DeviceScaleEnsuresTextQuality(device_scale_factor);
 }
 
 static bool ShouldUseTransitionCompositing(float device_scale_factor) {
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
 
   if (command_line.HasSwitch(switches::kDisableCompositingForTransition))
     return false;
 
   if (command_line.HasSwitch(switches::kEnableCompositingForTransition))
     return true;
 
   // TODO(ajuma): Re-enable this by default for high-DPI once the problem
   // of excessive layer promotion caused by overlap has been addressed.
   // http://crbug.com/178119.
   return false;
 }
 
+static bool ShouldUseAcceleratedFixedRootBackground(float device_scale_factor) {
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+
+  if (command_line.HasSwitch(switches::kDisableAcceleratedFixedRootBackground))
+    return false;
+
+  if (command_line.HasSwitch(switches::kEnableAcceleratedFixedRootBackground))
+    return true;
+
+  return DeviceScaleEnsuresTextQuality(device_scale_factor);
+}
+
 static FaviconURL::IconType ToFaviconType(blink::WebIconURL::Type type) {
   switch (type) {
     case blink::WebIconURL::TypeFavicon:
       return FaviconURL::FAVICON;
     case blink::WebIconURL::TypeTouch:
       return FaviconURL::TOUCH_ICON;
     case blink::WebIconURL::TypeTouchPrecomposed:
       return FaviconURL::TOUCH_PRECOMPOSED_ICON;
     case blink::WebIconURL::TypeInvalid:
       return FaviconURL::INVALID_ICON;
@@ skipping 317 matching lines @@
     did_show_ = true;
     CompleteInit();
   }
 
   g_view_map.Get().insert(std::make_pair(webview(), this));
   g_routing_id_view_map.Get().insert(std::make_pair(routing_id_, this));
   webview()->setDeviceScaleFactor(device_scale_factor_);
   webview()->settings()->setPreferCompositingToLCDTextEnabled(
       PreferCompositingToLCDText(device_scale_factor_));
   webview()->settings()->setAcceleratedCompositingForOverflowScrollEnabled(
-      PreferCompositingToLCDText(device_scale_factor_));
+      ShouldUseAcceleratedCompositingForOverflowScroll(device_scale_factor_));
   webview()->settings()->setAcceleratedCompositingForTransitionEnabled(
       ShouldUseTransitionCompositing(device_scale_factor_));
   webview()->settings()->setAcceleratedCompositingForFixedRootBackgroundEnabled(
-      PreferCompositingToLCDText(device_scale_factor_));
+      ShouldUseAcceleratedFixedRootBackground(device_scale_factor_));
   webview()->settings()->setCompositedScrollingForFramesEnabled(
       ShouldUseCompositedScrollingForFrames(device_scale_factor_));
 
   ApplyWebPreferences(webkit_preferences_, webview());
 
   webview()->settings()->setAllowConnectingInsecureWebSocket(
       command_line.HasSwitch(switches::kAllowInsecureWebSocketFromHttpsOrigin));
 
   RenderFrameProxy* proxy = NULL;
   if (params->proxy_routing_id != MSG_ROUTING_NONE) {
@@ skipping 2947 matching lines @@
                                         keep_selection);
 }
 
 void RenderViewImpl::SetDeviceScaleFactor(float device_scale_factor) {
   RenderWidget::SetDeviceScaleFactor(device_scale_factor);
   if (webview()) {
     webview()->setDeviceScaleFactor(device_scale_factor);
     webview()->settings()->setPreferCompositingToLCDTextEnabled(
         PreferCompositingToLCDText(device_scale_factor_));
     webview()->settings()->setAcceleratedCompositingForOverflowScrollEnabled(
-        PreferCompositingToLCDText(device_scale_factor_));
+        ShouldUseAcceleratedCompositingForOverflowScroll(device_scale_factor_));
     webview()->settings()->setAcceleratedCompositingForTransitionEnabled(
         ShouldUseTransitionCompositing(device_scale_factor_));
-    webview()
-        ->settings()
-        ->setAcceleratedCompositingForFixedRootBackgroundEnabled(
-            PreferCompositingToLCDText(device_scale_factor_));
+    webview()->settings()->
+        setAcceleratedCompositingForFixedRootBackgroundEnabled(
+            ShouldUseAcceleratedFixedRootBackground(device_scale_factor_));
     webview()->settings()->setCompositedScrollingForFramesEnabled(
         ShouldUseCompositedScrollingForFrames(device_scale_factor_));
   }
   if (auto_resize_mode_)
     AutoResizeCompositor();
 
   if (browser_plugin_manager_.get())
     browser_plugin_manager_->UpdateDeviceScaleFactor(device_scale_factor_);
 }
 
@@ skipping 547 matching lines @@
     std::vector<gfx::Size> sizes;
     ConvertToFaviconSizes(icon_urls[i].sizes(), &sizes);
     if (!url.isEmpty())
       urls.push_back(
           FaviconURL(url, ToFaviconType(icon_urls[i].iconType()), sizes));
   }
   SendUpdateFaviconURL(urls);
 }
 
 }  // namespace content