Revert of cc: Remove the --enable-partial-swap flag.

content/renderer/gpu/render_widget_compositor.cc

 // Copyright (c) 2013 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/gpu/render_widget_compositor.h"
 
 #include <limits>
 #include <string>
 
 #if defined(OS_ANDROID)
@@ skipping 152 matching lines @@
 
   if (cmd->HasSwitch(cc::switches::kTopControlsHideThreshold)) {
       std::string top_threshold_str =
           cmd->GetSwitchValueASCII(cc::switches::kTopControlsHideThreshold);
       double hide_threshold;
       if (base::StringToDouble(top_threshold_str, &hide_threshold) &&
           hide_threshold >= 0.f && hide_threshold <= 1.f)
         settings.top_controls_hide_threshold = hide_threshold;
   }
 
-  settings.partial_swap_enabled = widget->AllowPartialSwap();
+  settings.partial_swap_enabled = widget->AllowPartialSwap() &&
+      cmd->HasSwitch(cc::switches::kEnablePartialSwap);
   settings.background_color_instead_of_checkerboard =
       cmd->HasSwitch(cc::switches::kBackgroundColorInsteadOfCheckerboard);
   settings.show_overdraw_in_tracing =
       cmd->HasSwitch(cc::switches::kTraceOverdraw);
   settings.can_use_lcd_text = cc::switches::IsLCDTextEnabled();
   settings.use_pinch_virtual_viewport =
       cmd->HasSwitch(cc::switches::kEnablePinchVirtualViewport);
   settings.allow_antialiasing &=
       !cmd->HasSwitch(cc::switches::kDisableCompositedAntialiasing);
 
@@ skipping 440 matching lines @@
   widget_->OnSwapBuffersAborted();
 }
 
 void RenderWidgetCompositor::RateLimitSharedMainThreadContext() {
   cc::ContextProvider* provider =
       RenderThreadImpl::current()->SharedMainThreadContextProvider().get();
   provider->ContextGL()->RateLimitOffscreenContextCHROMIUM();
 }
 
 }  // namespace content