Put LayoutAnalyzer back behind disabled-by-default-blink.debug.layout.

Source/core/layout/LayoutAnalyzer.cpp

 // Copyright 2015 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 "config.h"
 #include "core/layout/LayoutAnalyzer.h"
 
 #include "core/frame/FrameView.h"
 #include "core/layout/LayoutObject.h"
 #include "core/layout/LayoutText.h"
 #include "platform/TracedValue.h"
 #include "public/platform/Platform.h"
 
 namespace blink {
 
 LayoutAnalyzer::Scope::Scope(const LayoutObject& o)
     : m_layoutObject(o)
     , m_analyzer(o.frameView()->layoutAnalyzer())
 {
-    m_analyzer.push(o);
+    if (m_analyzer)
+        m_analyzer->push(o);
 }
 
 LayoutAnalyzer::Scope::~Scope()
 {
-    m_analyzer.pop(m_layoutObject);
+    if (m_analyzer)
+        m_analyzer->pop(m_layoutObject);
 }
 
 void LayoutAnalyzer::reset()
 {
     m_startMs = currentTimeMS();
     m_depth = 0;
     for (size_t i = 0; i < NumCounters; ++i) {
         m_counters[i] = 0;
     }
 }
@@ skipping 98 matching lines @@
     case CharactersInLayoutObjectsThatAreTextAndCanNotUseTheSimpleFontCodePath: return "CharactersInLayoutObjectsThatAreTextAndCanNotUseTheSimpleFontCodePath";
     case LayoutObjectsThatAreTextAndCanUseTheSimpleFontCodePath: return "LayoutObjectsThatAreTextAndCanUseTheSimpleFontCodePath";
     case CharactersInLayoutObjectsThatAreTextAndCanUseTheSimpleFontCodePath: return "CharactersInLayoutObjectsThatAreTextAndCanUseTheSimpleFontCodePath";
     case TotalLayoutObjectsThatWereLaidOut: return "TotalLayoutObjectsThatWereLaidOut";
     }
     ASSERT_NOT_REACHED();
     return "";
 }
 
 } // namespace blink