Disable canvas hibernation on MacOSX to fix content loss issue

third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.cpp

 /*
  * Copyright (C) 2012 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:
  *
  * 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
@@ skipping 483 matching lines @@
         m_layer->setNearestNeighbor(m_filterQuality == kNone_SkFilterQuality);
 }
 
 void Canvas2DLayerBridge::setIsHidden(bool hidden)
 {
     bool newHiddenValue = hidden || m_destructionInProgress;
     if (m_isHidden == newHiddenValue)
         return;
 
     m_isHidden = newHiddenValue;
-    if (m_surface && isHidden() && !m_destructionInProgress && !m_hibernationScheduled) {
+    if (CANVAS2D_HIBERNATION_ENABLED && m_surface && isHidden() && !m_destructionInProgress && !m_hibernationScheduled) {
         if (m_layer)
             m_layer->clearTexture();
         m_logger->reportHibernationEvent(HibernationScheduled);
         m_hibernationScheduled = true;
         Platform::current()->currentThread()->scheduler()->postIdleTask(BLINK_FROM_HERE, WTF::bind<double>(&hibernateWrapper, m_weakPtrFactory.createWeakPtr()));
     }
     if (!isHidden() && m_softwareRenderingWhileHidden) {
         flushRecordingOnly();
         SkPaint copyPaint;
         copyPaint.setXfermodeMode(SkXfermode::kSrc_Mode);
@@ skipping 334 matching lines @@
     m_parentLayerBridge = other.m_parentLayerBridge;
 }
 
 void Canvas2DLayerBridge::Logger::reportHibernationEvent(HibernationEvent event)
 {
     DEFINE_STATIC_LOCAL(EnumerationHistogram, hibernationHistogram, ("Canvas.HibernationEvents", HibernationEventCount));
     hibernationHistogram.count(event);
 }
 
 } // namespace blink