[SPInvalidation] Fix caret paint invalidation in sub frames

third_party/WebKit/Source/core/editing/FrameCaret.cpp

 /*
  * Copyright (C) 2004, 2008, 2009, 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
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@@ skipping 11 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "core/editing/FrameCaret.h"
 
 #include "core/editing/EditingUtilities.h"
 #include "core/editing/Editor.h"
 #include "core/editing/SelectionEditor.h"
 #include "core/editing/commands/CompositeEditCommand.h"
+#include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/html/TextControlElement.h"
 #include "core/layout/LayoutTheme.h"
-#include "core/layout/api/LayoutViewItem.h"
+#include "core/layout/api/LayoutPartItem.h"
 #include "core/page/Page.h"
 #include "core/paint/PaintLayer.h"
 #include "public/platform/WebTraceLocation.h"
 
 namespace blink {
 
 FrameCaret::FrameCaret(LocalFrame* frame,
                        const SelectionEditor& selectionEditor)
     : m_selectionEditor(&selectionEditor),
       m_frame(frame),
@@ skipping 88 matching lines @@
   updateAppearance();
 }
 
 void FrameCaret::setCaretRectNeedsUpdate() {
   if (m_caretRectDirty)
     return;
   m_caretRectDirty = true;
 
   if (Page* page = m_frame->page())
     page->animator().scheduleVisualUpdate(m_frame->localFrameRoot());
+
+  // Ensure the frame will be checked for paint invalidation during

[pdr., 2016/12/22 01:08:18]

Without spinvalidation, how are carets marked as needing paint invalidation?

It looks like we have some logic to invalidate them in
FrameCaret::invalidateCaretRect... are we missing a call to
"node->layoutObject()->setMayNeedPaintInvalidation" there, which would handle
crossing frames?

[Xianzhu, 2016/12/22 01:31:52]

Without spinvalidation, we always walk all of the FrameViews:
https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/frame/Fra....

Actually we could remove the walk for non-spinvalidation with unconditional
setMayNeedPaintInvalidation here. May consider a follow-up.

+  // PrePaintTreeWalk.
+  if (RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled()) {
+    if (auto layoutItem = m_frame->ownerLayoutItem())

[pdr., 2016/12/22 01:08:18]

I think with LayoutItem you need to check !layoutItem.isNull().
Can you switch this to just using LayoutObject instead?
if (auto* layoutObject = m_frame->ownerLayoutObject())
    layoutObject->setMayNeedPaintInvalidation();

[Xianzhu, 2016/12/22 01:31:52]

The above is equivalent to "if (auto* layoutObject =
m_frame->ownerLayoutObject())", using LayoutItem::operator LayoutObject* (which
will be operator bool).

+      layoutItem.setMayNeedPaintInvalidation();
+  }
 }
 
 bool FrameCaret::caretPositionIsValidForDocument(
     const Document& document) const {
   if (!isActive())
     return true;
 
   return caretPosition().document() == document && !caretPosition().isOrphan();
 }
 
@@ skipping 135 matching lines @@
 
 void FrameCaret::caretBlinkTimerFired(TimerBase*) {
   DCHECK_EQ(m_caretVisibility, CaretVisibility::Visible);
   if (isCaretBlinkingSuspended() && m_shouldPaintCaret)
     return;
   m_shouldPaintCaret = !m_shouldPaintCaret;
   setCaretRectNeedsUpdate();
 }
 
 }  // namespace blink