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

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

Index: third_party/WebKit/Source/core/style/ComputedStyle.cpp
diff --git a/third_party/WebKit/Source/core/style/ComputedStyle.cpp b/third_party/WebKit/Source/core/style/ComputedStyle.cpp
index 3a671d051c066787e9e0174febf1e9470cb43c82..9c9594ee8675df304b152fd147f5306caf22d0e7 100644
--- a/third_party/WebKit/Source/core/style/ComputedStyle.cpp
+++ b/third_party/WebKit/Source/core/style/ComputedStyle.cpp
@@ -562,10 +562,14 @@ bool ComputedStyle::diffNeedsFullLayoutAndPaintInvalidation(const ComputedStyle&
             || 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;