Fix paint invalidation and painting for composited-scrolling input elements.

third_party/WebKit/Source/core/editing/CaretBase.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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 16 matching lines @@
 
 #include "core/editing/EditingUtilities.h"
 #include "core/editing/VisibleUnits.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/Settings.h"
 #include "core/layout/LayoutBlock.h"
 #include "core/layout/LayoutView.h"
 #include "core/layout/api/LayoutBlockItem.h"
 #include "core/layout/api/LayoutItem.h"
 #include "core/paint/PaintInfo.h"
+#include "core/paint/PaintLayer.h"
 #include "platform/graphics/GraphicsContext.h"
+#include "platform/graphics/GraphicsLayer.h"
+#include "platform/graphics/paint/DrawingRecorder.h"
 
 namespace blink {
 
 CaretBase::CaretBase(CaretVisibility visibility)
     : m_caretVisibility(visibility)
 {
 }
 
 CaretBase::~CaretBase() = default;
 
@@ skipping 84 matching lines @@
 {
     LayoutBlock* caretPainter = caretLayoutObject(node);
     if (!caretPainter)
         return IntRect();
 
     LayoutRect localRect(rect);
     caretPainter->flipForWritingMode(localRect);
     return caretPainter->localToAbsoluteQuad(FloatRect(localRect)).enclosingBoundingBox();
 }
 
+DisplayItemClient* CaretBase::displayItemClientForCaret(Node* node)
+{
+    LayoutBlock* caretLayoutBlock = caretLayoutObject(node);
+    if (caretLayoutBlock->usesCompositedScrolling())

[pdr., 2016/08/25 22:07:11]

usesCompositedScrolling() can change dynamically. Do we need to tell the old
client to invalidate or paint when this occurs?

+        return static_cast<DisplayItemClient*>(caretLayoutBlock->layer()->graphicsLayerBackingForScrolling());
+    return caretLayoutBlock;
+}
+
 // TODO(yoichio): |node| is FrameSelection::m_previousCaretNode and this is bad
 // design. We should use only previous layoutObject or Rectangle to invalidate
 // old caret.
 void CaretBase::invalidateLocalCaretRect(Node* node, const LayoutRect& rect)
 {
-    LayoutBlockItem caretPainter = LayoutBlockItem(caretLayoutObject(node));
-    if (!caretPainter)
+    LayoutBlock* caretLayoutBlock = caretLayoutObject(node);
+    if (!caretLayoutBlock)
         return;
 
     // FIXME: Need to over-paint 1 pixel to workaround some rounding problems.
     // https://bugs.webkit.org/show_bug.cgi?id=108283
     LayoutRect inflatedRect = rect;
     inflatedRect.inflate(LayoutUnit(1));
 
-    // FIXME: We should use mapLocalToAncestor() since we know we're not un-rooted.
-    mapCaretRectToCaretPainter(LayoutItem(node->layoutObject()), caretPainter, inflatedRect);
+    // // FIXME: We should not allow paint invalidation out of paint invalidation state. crbug.com/457415

[pdr., 2016/08/25 22:07:11]

Nit: Your comment has a comment

[chrishtr, 2016/08/26 16:02:25]

Done.

+    DisablePaintInvalidationStateAsserts disabler;
 
-    // FIXME: We should not allow paint invalidation out of paint invalidation state. crbug.com/457415
-    DisablePaintInvalidationStateAsserts disabler;
-    caretPainter.invalidatePaintRectangle(inflatedRect);
+    node->layoutObject()->invalidatePaintRectangle(inflatedRect, displayItemClientForCaret(node));
 }
 
 bool CaretBase::shouldRepaintCaret(Node& node) const
 {
     // If PositionAnchorType::BeforeAnchor or PositionAnchorType::AfterAnchor,
     // carets need to be repainted not only when the node is contentEditable but
     // also when its parentNode() is contentEditable.
     node.document().updateStyleAndLayoutTree();
     return hasEditableStyle(node) || (node.parentNode() && hasEditableStyle(*node.parentNode()));
 }
@@ skipping 18 matching lines @@
         if (hasEditableStyle(*node) || shouldRepaintCaret(view))
             invalidateLocalCaretRect(node, localCaretRectWithoutUpdate());
     }
 }
 
 void CaretBase::paintCaret(Node* node, GraphicsContext& context, const LayoutPoint& paintOffset) const
 {
     if (m_caretVisibility == CaretVisibility::Hidden)
         return;
 
+    if (DrawingRecorder::useCachedDrawingIfPossible(context, *displayItemClientForCaret(node), DisplayItem::Caret))
+        return;
+
     LayoutRect drawingRect = localCaretRectWithoutUpdate();
     if (LayoutBlock* layoutObject = caretLayoutObject(node))
         layoutObject->flipForWritingMode(drawingRect);
     drawingRect.moveBy(roundedIntPoint(paintOffset));
 
     Color caretColor = Color::black;
 
     Element* element;
     if (node->isElementNode())
         element = toElement(node);
     else
         element = node->parentElement();
 
     if (element && element->layoutObject())
         caretColor = element->layoutObject()->resolveColor(CSSPropertyColor);
 
+    DrawingRecorder drawingRecorder(context, *displayItemClientForCaret(node), DisplayItem::Caret, FloatRect(drawingRect));
+
     context.fillRect(FloatRect(drawingRect), caretColor);
 }
 
 void CaretBase::setCaretVisibility(CaretVisibility visibility)
 {
     m_caretVisibility = visibility;
 }
 
 } // namespace blink