Table cell background painting

third_party/WebKit/Source/core/layout/LayoutTableCol.cpp

Index: third_party/WebKit/Source/core/layout/LayoutTableCol.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutTableCol.cpp b/third_party/WebKit/Source/core/layout/LayoutTableCol.cpp
index aaf594c9e7481959cd7c6dcd0ae31103047c1b45..a26f48178c41e30133b09a57113a0e6701b9cf31 100644
--- a/third_party/WebKit/Source/core/layout/LayoutTableCol.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutTableCol.cpp
@@ -110,15 +110,17 @@ bool LayoutTableCol::canHaveChildren() const
 
 LayoutRect LayoutTableCol::clippedOverflowRectForPaintInvalidation(const LayoutBoxModelObject* paintInvalidationContainer, const PaintInvalidationState* paintInvalidationState) const
 {
-    // For now, just paint invalidate the whole table.
-    // FIXME: Find a better way to do this, e.g., need to paint invalidate all the cells that we
-    // might have propagated a background color or borders into.
-    // FIXME: check for paintInvalidationContainer each time here?
+    // Entire table gets invalidated, instead of invalidating
+    // every cell in the column.
+    // This is simpler, but suboptimal.
 
-    LayoutTable* parentTable = table();
-    if (!parentTable)
+    LayoutTable* table = this->table();
+    if (!table)
         return LayoutRect();
-    return parentTable->clippedOverflowRectForPaintInvalidation(paintInvalidationContainer, paintInvalidationState);
+    LayoutRect r = table->visualOverflowRect();
+    r.setLocation(LayoutPoint(0, 0));

[Xianzhu, 2016/03/15 17:24:39]

The correctness of this method depends on the fact that LayoutTableCol is not
laid out to have an offset from the table (this is why I asked you to add the
test). Please add
   // The correctness of this method depends on the fact that LayoutTableCol's
   // location is always zero.
   ASSERT(this->location() == LayoutPoint());

[Xianzhu, 2016/03/15 17:24:39]

The above line should be removed. visualOverflowRect is in space of the object.
Normally its location is zero, but if the object has visual overflow, the
location will be negative and should be counted in the mapped result.

[atotic1, 2016/03/15 18:50:50]

Done.

[atotic1, 2016/03/15 18:50:51]

Done.

+    mapToVisibleRectInAncestorSpace(paintInvalidationContainer, r, paintInvalidationState);
+    return r;
 }
 
 void LayoutTableCol::imageChanged(WrappedImagePtr, const IntRect*)