Introduce DragController::hasCaretIn()

This patch introduces |DragController::hasCaretIn()| as replacement of
|DragController::caretLayoutObject()| and |DragController::isContentEditable()|
to provide high-level API for improving code health.

BUG=n/a
TEST=n/a; no behavior changes

Review-Url: https://codereview.chromium.org/2272343002
Cr-Commit-Position: refs/heads/master@{#414381}

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

@@ -26,6 +26,7 @@
 #include "core/editing/DragCaretController.h"
 
 #include "core/editing/EditingUtilities.h"
+#include "core/frame/Settings.h"
 #include "core/layout/api/LayoutViewItem.h"
 #include "core/paint/PaintLayer.h"
 
@@ -41,6 +42,19 @@ DragCaretController* DragCaretController::create()
     return new DragCaretController;
 }
 
+bool DragCaretController::hasCaretIn(const LayoutBlock& layoutBlock) const
+{
+    Node* node = m_position.deepEquivalent().anchorNode();
+    if (!node)
+        return false;
+    if (layoutBlock != CaretBase::caretLayoutObject(node))
+        return false;
+    if (rootEditableElementOf(m_position))
+        return true;
+    Settings* settings = node->ownerDocument()->frame()->settings();
+    return settings && settings->caretBrowsingEnabled();
+}
+
 bool DragCaretController::isContentRichlyEditable() const
 {
     return isRichlyEditablePosition(m_position.deepEquivalent());
@@ -102,16 +116,6 @@ DEFINE_TRACE(DragCaretController)
     visitor->trace(m_caretBase);
 }
 
-LayoutBlock* DragCaretController::caretLayoutObject() const
-{
-    return CaretBase::caretLayoutObject(m_position.deepEquivalent().anchorNode());
-}
-
-bool DragCaretController::isContentEditable() const
-{
-    return rootEditableElementOf(m_position);
-}
-
 void DragCaretController::paintDragCaret(LocalFrame* frame, GraphicsContext& context, const LayoutPoint& paintOffset) const
 {
     if (m_position.deepEquivalent().anchorNode()->document().frame() == frame)

third_party/WebKit/Source/core/editing/DragCaretController.h

@@ -35,10 +35,9 @@ class DragCaretController final : public GarbageCollectedFinalized<DragCaretCont
 public:
     static DragCaretController* create();
 
-    LayoutBlock* caretLayoutObject() const;
     void paintDragCaret(LocalFrame*, GraphicsContext&, const LayoutPoint&) const;
 
-    bool isContentEditable() const;
+    bool hasCaretIn(const LayoutBlock&) const;
     bool isContentRichlyEditable() const;
 
     bool hasCaret() const { return m_position.isNotNull(); }

third_party/WebKit/Source/core/layout/LayoutBlock.cpp

@@ -1607,7 +1607,7 @@ bool LayoutBlock::hasDragCaret() const
 {
     LocalFrame* frame = this->frame();
     DragCaretController& dragCaretController = frame->page()->dragCaretController();
-    return dragCaretController.caretLayoutObject() == this && (dragCaretController.isContentEditable() || caretBrowsingEnabled(frame));
+    return dragCaretController.hasCaretIn(*this);
 }
 
 LayoutRect LayoutBlock::localCaretRect(InlineBox* inlineBox, int caretOffset, LayoutUnit* extraWidthToEndOfLine)