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..8c5266746b90d9d578f1cd6002e48414d5051571 100644
--- a/third_party/WebKit/Source/core/layout/LayoutTableCol.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutTableCol.cpp
@@ -110,15 +110,14 @@ 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?
-
-    LayoutTable* parentTable = table();
-    if (!parentTable)
+    // FIXME: Issue paint invalidation of only the rect the image paints in.

[Xianzhu, 2016/03/14 20:40:18]

"FIXME:" style has been obsoleted by "TODO(name)". If you do feel we should fix
it, please add "TODO(atotic)", otherwise just explain why we are doing in the
non-optimal way, like

  // Just invalidate paint of the whole table to avoid the complexity to ....

+    LayoutTable* table = this->table();
+    if (!table)
         return LayoutRect();
-    return parentTable->clippedOverflowRectForPaintInvalidation(paintInvalidationContainer, paintInvalidationState);
+    LayoutRect r = table->frameRect();

[Xianzhu, 2016/03/14 20:40:18]

This is incorrect because frameRect doesn't include overflows and consider
clippings. You might need to still call
table->clippedOverflowRectForPaintInvalidation() and adjust the wrong offset.

+    r.setLocation(LayoutPoint(0, 0));
+    mapToVisibleRectInAncestorSpace(paintInvalidationContainer, r, paintInvalidationState);
+    return r;
 }
 
 void LayoutTableCol::imageChanged(WrappedImagePtr, const IntRect*)