Switch to using accessibilityEnabled and inlineTextBoxAccessibilityEnabled from settings

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 15 matching lines @@
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "core/rendering/RenderBlockFlow.h"
 
 #include "core/accessibility/AXObjectCache.h"
 #include "core/frame/FrameView.h"
+#include "core/frame/LocalFrame.h"
+#include "core/frame/Settings.h"
 #include "core/rendering/HitTestLocation.h"
 #include "core/rendering/RenderFlowThread.h"
 #include "core/rendering/RenderLayer.h"
 #include "core/rendering/RenderMultiColumnFlowThread.h"
 #include "core/rendering/RenderPagedFlowThread.h"
 #include "core/rendering/RenderText.h"
 #include "core/rendering/RenderView.h"
 #include "core/rendering/TextAutosizer.h"
 #include "core/rendering/line/LineWidth.h"
 #include "core/rendering/svg/SVGTextRunRenderingContext.h"
@@ skipping 1730 matching lines @@
     RenderBlock::computeOverflow(oldClientAfterEdge, recomputeFloats);
     if (!hasColumns() && (recomputeFloats || createsBlockFormattingContext() || hasSelfPaintingLayer()))
         addOverflowFromFloats();
 }
 
 RootInlineBox* RenderBlockFlow::createAndAppendRootInlineBox()
 {
     RootInlineBox* rootBox = createRootInlineBox();
     m_lineBoxes.appendLineBox(rootBox);
 
-    if (UNLIKELY(AXObjectCache::accessibilityEnabled()) && m_lineBoxes.firstLineBox() == rootBox) {
+    Settings* settings = frame()->settings();
+    if (UNLIKELY(settings && settings->accessibilityEnabled()) && m_lineBoxes.firstLineBox() == rootBox) {

[abarth-chromium, 2014/08/23 05:59:11]

This is sad.  We're adding a ton more branches to this codepath.

[aboxhall, 2014/08/27 15:26:33]

I don't follow.

[dmazzoni, 2014/08/27 16:17:15]

I think Adam is saying that this function (createAndAppendRootInlineBox) is
called thousands of times during layout, and testing whether accessibility is
enabled every time is expensive - and this change potentially makes it worse.

I think it might be possible to get rid of this test entirely. I filed
http://crbug.com/408159, let me see what the implications are if we get rid of
this code and the accessibility logic that depended on it.

         if (AXObjectCache* cache = document().existingAXObjectCache())
             cache->recomputeIsIgnored(this);
     }
 
     return rootBox;
 }
 
 void RenderBlockFlow::deleteLineBoxTree()
 {
     if (containsFloats())
@@ skipping 1128 matching lines @@
 RenderBlockFlow::RenderBlockFlowRareData& RenderBlockFlow::ensureRareData()
 {
     if (m_rareData)
         return *m_rareData;
 
     m_rareData = adoptPtrWillBeNoop(new RenderBlockFlowRareData(this));
     return *m_rareData;
 }
 
 } // namespace blink