Fix shouldPaint issue when a composited floating iframe becomes non-self-painting

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

Index: third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp b/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
index 49d25e0e6202d58062c54e21c0851061e72b01a4..5bfc1184243596c90fb20540664da794781d1ff6 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
@@ -3998,7 +3998,8 @@ bool LayoutBlockFlow::hitTestFloats(HitTestResult& result,
   for (FloatingObjectSetIterator it = floatingObjectSet.end(); it != begin;) {
     --it;
     const FloatingObject& floatingObject = *it->get();
-    if (floatingObject.shouldPaint()) {
+    if (floatingObject.shouldPaint() &&
+        !floatingObject.layoutObject()->hasSelfPaintingLayer()) {

[chrishtr, 2017/01/25 20:47:57]

Why do you need this?

[Xianzhu, 2017/01/25 21:03:25]

This is a part of the revert, which I didn't look very closely at.
This is like the revert in BlockFlowPainter.cpp.
Perhaps it should be a DCHECK.

Added a TODO here, like I did in BlockFlowPainter.cpp.

This CL needs to be merged into M56, so I would like to take the safe side.

       LayoutUnit xOffset = xPositionForFloatIncludingMargin(floatingObject) -
                            floatingObject.layoutObject()->location().x();
       LayoutUnit yOffset = yPositionForFloatIncludingMargin(floatingObject) -