Disable FTA when max multiplier is 1.

Source/core/rendering/RenderBlockFlow.cpp

 /*
  * Copyright (C) 2013 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 335 matching lines @@
     LayoutUnit afterEdge = borderAfter() + paddingAfter() + scrollbarLogicalHeight();
     LayoutUnit previousHeight = logicalHeight();
     setLogicalHeight(beforeEdge);
 
     m_repaintLogicalTop = 0;
     m_repaintLogicalBottom = 0;
     LayoutUnit maxFloatLogicalBottom = 0;
     if (!firstChild() && !isAnonymousBlock())
         setChildrenInline(true);
 
-    FastTextAutosizer::LayoutScope fastTextAutosizerLayoutScope(document(), this);
+    FastTextAutosizer::LayoutScope fastTextAutosizerLayoutScope(this);
 
     if (childrenInline())
         layoutInlineChildren(relayoutChildren, m_repaintLogicalTop, m_repaintLogicalBottom, afterEdge);
     else
         layoutBlockChildren(relayoutChildren, maxFloatLogicalBottom, layoutScope, beforeEdge, afterEdge);
 
     if (frameView()->partialLayout().isStopping()) {
         statePusher.pop();
         return true;
     }
@@ skipping 2465 matching lines @@
 RenderBlockFlow::RenderBlockFlowRareData& RenderBlockFlow::ensureRareData()
 {
     if (m_rareData)
         return *m_rareData;
 
     m_rareData = adoptPtr(new RenderBlockFlowRareData(this));
     return *m_rareData;
 }
 
 } // namespace WebCore