Implement incremental paint property tree rebuilding

third_party/WebKit/Source/core/frame/FrameView.cpp

Index: third_party/WebKit/Source/core/frame/FrameView.cpp
diff --git a/third_party/WebKit/Source/core/frame/FrameView.cpp b/third_party/WebKit/Source/core/frame/FrameView.cpp
index 419d75ec172dbeecae388a6c79699fff76fb6e8e..56638a335c8a433516fa2bc5249a72fd7400f600 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.cpp
+++ b/third_party/WebKit/Source/core/frame/FrameView.cpp
@@ -3377,6 +3377,8 @@ void FrameView::frameRectsChanged() {
   setNeedsUpdateViewportIntersection();
   for (const auto& child : m_children)
     child->frameRectsChanged();
+
+  setPaintPropertiesInvalid();

[chrishtr, 2016/10/21 22:03:09]

Add a brief comment explaining which property tree nodes are invalidated by
changed frame rect.

[pdr., 2016/10/26 03:10:48]

Done

 }
 
 void FrameView::setLayoutSizeInternal(const IntSize& size) {
@@ -3615,6 +3617,7 @@ void FrameView::didChangeScrollOffset() {
   frame().loader().client()->didChangeScrollOffset();
   if (frame().isMainFrame())
     frame().host()->chromeClient().mainFrameScrollOffsetChanged();
+  setPaintPropertiesInvalid();

[chrishtr, 2016/10/21 22:03:09]

Add a brief comment explaining which property tree nodes are invalidated by
changed scroll.

(it's the scroll offset one right? and it only needs its matrix contents
adjusted?)

[pdr., 2016/10/26 03:10:48]

Done. I tightened these invalidations up a bit as well (only in scroll offset
and contents size changed functions now).

 }
 
 void FrameView::clearScrollAnchor() {