[css-grid] Only force full invalidation when grid item data change

third_party/WebKit/Source/core/style/ComputedStyle.cpp

 /*
  * Copyright (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2011 Adobe Systems Incorporated. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 544 matching lines @@
 
     if (m_rareNonInheritedData.get() != other.m_rareNonInheritedData.get()) {
         if (m_rareNonInheritedData->m_appearance != other.m_rareNonInheritedData->m_appearance
             || m_rareNonInheritedData->marginBeforeCollapse != other.m_rareNonInheritedData->marginBeforeCollapse
             || m_rareNonInheritedData->marginAfterCollapse != other.m_rareNonInheritedData->marginAfterCollapse
             || m_rareNonInheritedData->lineClamp != other.m_rareNonInheritedData->lineClamp
             || m_rareNonInheritedData->textOverflow != other.m_rareNonInheritedData->textOverflow
             || m_rareNonInheritedData->m_shapeMargin != other.m_rareNonInheritedData->m_shapeMargin
             || m_rareNonInheritedData->m_order != other.m_rareNonInheritedData->m_order
             || m_rareNonInheritedData->m_grid.get() != other.m_rareNonInheritedData->m_grid.get()
-            || m_rareNonInheritedData->m_gridItem.get() != other.m_rareNonInheritedData->m_gridItem.get()
             || m_rareNonInheritedData->hasFilters() != other.m_rareNonInheritedData->hasFilters())
             return true;
 
+        const StyleGridItemData* gridItemDataA = m_rareNonInheritedData->m_gridItem.get();
+        const StyleGridItemData* gridItemDataB = m_rareNonInheritedData->m_gridItem.get();

[cbiesinger, 2016/08/19 18:55:13]

This needs an "other"...

[jfernandez, 2016/08/19 20:41:21]

Done.

+        if (!(gridItemDataA == gridItemDataB) || (gridItemDataA && gridItemDataA && *gridItemDataA == *gridItemDataB))

[cbiesinger, 2016/08/19 18:55:13]

gridItemDataA && gridItemDataA <-- needs to be B

Also, I'm confused by this entire condition. Is it even possible for one of
these to be null? And if so, you should return true if one is null but not the
other, right? I also think you misplaced the first closing parenthesis.

[jfernandez, 2016/08/19 20:41:22]

Right.
I think it's kind of defensive logic. Do you think we should remove it ? I'm
following the same pattern than m_counterDirectives some lines below
. 
You right, I made a mistake with the parenthesis. 

+            return true;
+
         if (m_rareNonInheritedData->m_deprecatedFlexibleBox.get() != other.m_rareNonInheritedData->m_deprecatedFlexibleBox.get()
             && *m_rareNonInheritedData->m_deprecatedFlexibleBox.get() != *other.m_rareNonInheritedData->m_deprecatedFlexibleBox.get())
             return true;
 
         if (m_rareNonInheritedData->m_flexibleBox.get() != other.m_rareNonInheritedData->m_flexibleBox.get()
             && *m_rareNonInheritedData->m_flexibleBox.get() != *other.m_rareNonInheritedData->m_flexibleBox.get())
             return true;
 
         if (m_rareNonInheritedData->m_multiCol.get() != other.m_rareNonInheritedData->m_multiCol.get()
             && *m_rareNonInheritedData->m_multiCol.get() != *other.m_rareNonInheritedData->m_multiCol.get())
@@ skipping 1409 matching lines @@
         if (value < 0)
             fvalue -= 0.5f;
         else
             fvalue += 0.5f;
     }
 
     return roundForImpreciseConversion<int>(fvalue / zoomFactor);
 }
 
 } // namespace blink