Remove the forceCompositingMode setting.

Source/core/rendering/compositing/RenderLayerCompositor.cpp

 /*
  * Copyright (C) 2009, 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 165 matching lines @@
 
 bool RenderLayerCompositor::compositingLayersNeedRebuild()
 {
     // enableCompositingModeIfNeeded can set the m_compositingLayersNeedRebuild bit.
     ASSERT(!m_rootShouldAlwaysCompositeDirty);
     return m_compositingLayersNeedRebuild;
 }
 
 bool RenderLayerCompositor::rootShouldAlwaysComposite() const
 {
-    Settings* settings = m_renderView.document().settings();
-    bool shouldComposite = settings->forceCompositingMode() && m_hasAcceleratedCompositing;
-    if (shouldComposite && !m_renderView.frame()->isMainFrame())
+    if (m_hasAcceleratedCompositing && !m_renderView.frame()->isMainFrame())
         return m_compositingReasonFinder.requiresCompositingForScrollableFrame();
-    return shouldComposite;
+    return m_hasAcceleratedCompositing;
 }
 
 void RenderLayerCompositor::updateAcceleratedCompositingSettings()
 {
     m_compositingReasonFinder.updateTriggers();
 
     bool hasAcceleratedCompositing = m_renderView.document().settings()->acceleratedCompositingEnabled();
 
     // FIXME: Is this needed? It was added in https://bugs.webkit.org/show_bug.cgi?id=26651.
     // No tests fail if it's deleted.
@@ skipping 1219 matching lines @@
     } else if (graphicsLayer == m_scrollLayer.get()) {
         name = "LocalFrame Scrolling Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace WebCore