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

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

Index: third_party/WebKit/Source/core/editing/CaretBase.cpp
diff --git a/third_party/WebKit/Source/core/editing/CaretBase.cpp b/third_party/WebKit/Source/core/editing/CaretBase.cpp
index 9781217137343403d52c8a7a8792b44c9c4e04f2..c464127f8984c808251c992f0e0944ab876e67a0 100644
--- a/third_party/WebKit/Source/core/editing/CaretBase.cpp
+++ b/third_party/WebKit/Source/core/editing/CaretBase.cpp
@@ -34,7 +34,10 @@
 #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 {
 
@@ -139,13 +142,21 @@ IntRect CaretBase::absoluteBoundsForLocalRect(Node* node, const LayoutRect& rect
     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.
@@ -153,12 +164,10 @@ void CaretBase::invalidateLocalCaretRect(Node* node, const LayoutRect& rect)
     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
+    // // 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;
-    caretPainter.invalidatePaintRectangle(inflatedRect);
+
+    node->layoutObject()->invalidatePaintRectangle(inflatedRect, displayItemClientForCaret(node));
 }
 
 bool CaretBase::shouldRepaintCaret(Node& node) const
@@ -197,6 +206,9 @@ void CaretBase::paintCaret(Node* node, GraphicsContext& context, const LayoutPoi
     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);
@@ -213,6 +225,8 @@ void CaretBase::paintCaret(Node* node, GraphicsContext& context, const LayoutPoi
     if (element && element->layoutObject())
         caretColor = element->layoutObject()->resolveColor(CSSPropertyColor);
 
+    DrawingRecorder drawingRecorder(context, *displayItemClientForCaret(node), DisplayItem::Caret, FloatRect(drawingRect));
+
     context.fillRect(FloatRect(drawingRect), caretColor);
 }