Add CaretBase::m_caretPainter, and compute caretBrowsing lazily.

Source/core/editing/Caret.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 22 matching lines @@
 #include "core/frame/Settings.h"
 #include "core/html/HTMLTextFormControlElement.h"
 #include "core/layout/LayoutBlock.h"
 #include "core/layout/LayoutView.h"
 #include "core/paint/DeprecatedPaintLayer.h"
 #include "platform/graphics/GraphicsContext.h"
 
 namespace blink {
 
 CaretBase::CaretBase(CaretVisibility visibility)
-    : m_caretVisibility(visibility)
+    : m_caretPainter(nullptr)
+    , m_caretVisibility(visibility)
 {
 }
 
 DragCaretController::DragCaretController()
     : CaretBase(Visible)
 {
 }
 
 PassOwnPtrWillBeRawPtr<DragCaretController> DragCaretController::create()
 {
@@ skipping 54 matching lines @@
     clear();
 }
 
 DEFINE_TRACE(DragCaretController)
 {
     visitor->trace(m_position);
 }
 
 void CaretBase::clearCaretRect()
 {
+    m_caretPainter = nullptr;
     m_caretLocalRect = LayoutRect();
 }
 
 static inline bool caretRendersInsideNode(Node* node)
 {
     return node && !isRenderedTableElement(node) && !editingIgnoresContent(node);
 }
 
 LayoutBlock* CaretBase::caretLayoutObject(Node* node)
 {
@@ skipping 27 matching lines @@
         caretRect.move(caretLayoutObject->offsetFromContainer(containerObject, caretRect.location()));
         caretLayoutObject = containerObject;
     }
 
     if (unrooted)
         caretRect = LayoutRect();
 }
 
 bool CaretBase::updateCaretRect(Document* document, const PositionWithAffinity& caretPosition)
 {
+    m_caretPainter = nullptr;
     m_caretLocalRect = LayoutRect();
 
     if (caretPosition.position().isNull())
         return false;
 
     ASSERT(caretPosition.position().deprecatedNode()->layoutObject());
 
     // First compute a rect local to the layoutObject at the selection start.
     LayoutObject* layoutObject;
     m_caretLocalRect = localCaretRectOfPosition(caretPosition, layoutObject);
 
     // Get the layoutObject that will be responsible for painting the caret
     // (which is either the layoutObject we just found, or one of its containers).
-    LayoutBlock* caretPainter = caretLayoutObject(caretPosition.position().deprecatedNode());
+    m_caretPainter = caretLayoutObject(caretPosition.position().deprecatedNode());
 
-    mapCaretRectToCaretPainter(layoutObject, caretPainter, m_caretLocalRect);
+    mapCaretRectToCaretPainter(layoutObject, m_caretPainter, m_caretLocalRect);
 
     return true;
 }
 
 bool CaretBase::updateCaretRect(Document* document, const VisiblePosition& caretPosition)
 {
     return updateCaretRect(document, PositionWithAffinity(caretPosition.deepEquivalent(), caretPosition.affinity()));
 }
 
-LayoutBlock* DragCaretController::caretLayoutObject() const
-{
-    return CaretBase::caretLayoutObject(m_position.deepEquivalent().deprecatedNode());
-}
-
 IntRect CaretBase::absoluteBoundsForLocalRect(Node* node, const LayoutRect& rect) const
 {
     LayoutBlock* caretPainter = caretLayoutObject(node);
     if (!caretPainter)
         return IntRect();
 
     LayoutRect localRect(rect);
     caretPainter->flipForWritingMode(localRect);
     return caretPainter->localToAbsoluteQuad(FloatRect(localRect)).enclosingBoundingBox();
 }
@@ skipping 73 matching lines @@
     context->fillRect(caret, caretColor);
 }
 
 void DragCaretController::paintDragCaret(LocalFrame* frame, GraphicsContext* p, const LayoutPoint& paintOffset, const LayoutRect& clipRect) const
 {
     if (m_position.deepEquivalent().deprecatedNode()->document().frame() == frame)
         paintCaret(m_position.deepEquivalent().deprecatedNode(), p, paintOffset, clipRect);
 }
 
 }