Use Position instead of VisiblePosition for SurroundingText.

Source/core/editing/SurroundingText.cpp

 /*
  * Copyright (C) 2012 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 14 matching lines @@
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (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 "config.h"
 #include "core/editing/SurroundingText.h"
 
 #include "core/dom/Document.h"
+#include "core/dom/Position.h"
 #include "core/dom/Range.h"
 #include "core/editing/TextIterator.h"
-#include "core/editing/VisiblePosition.h"
-#include "core/editing/VisibleUnits.h"
 
 namespace WebCore {
 
-SurroundingText::SurroundingText(const VisiblePosition& visiblePosition, unsigned maxLength)
+SurroundingText::SurroundingText(const Position& position, unsigned maxLength)
     : m_positionOffsetInContent(0)
 {
-    if (visiblePosition.isNull())
+    if (position.isNull())
         return;
 
     const unsigned halfMaxLength = maxLength / 2;
-    CharacterIterator forwardIterator(makeRange(visiblePosition, endOfDocument(visiblePosition)).get(), TextIteratorStopsOnFormControls);
+
+    Document* document = position.document();
+    ASSERT(document);

[yosin_UTC9, 2014/06/04 01:04:05]

nit: We don't need to have this |ASSERT(document)|, because we check
|Position.isNull()| on L44.

[yosin_UTC9, 2014/06/04 01:13:10]

How about unify |Position::isNull| and |Position::document|?

Document* document = position.document();
if (!document)
   return;

[mlamouri (slow - plz ping), 2014/06/04 09:52:12]

Done.

+
+    // The forward range starts at the selection end and ends at the document's
+    // end. It will then be updated to only contain the text in the text in the
+    // right range around the selection.
+    RefPtrWillBeRawPtr<Range> forwardRange = rangeOfContents(document);
+    forwardRange->setStart(position);
+    CharacterIterator forwardIterator(forwardRange.get(), TextIteratorStopsOnFormControls);
     if (!forwardIterator.atEnd())
         forwardIterator.advance(maxLength - halfMaxLength);
 
-    Position position = visiblePosition.deepEquivalent().parentAnchoredEquivalent();
-    Document* document = position.document();
-    ASSERT(document);
-    RefPtrWillBeRawPtr<Range> forwardRange = forwardIterator.range();
+    forwardRange = forwardIterator.range();
     if (!forwardRange || !Range::create(*document, position, forwardRange->startPosition())->text().length()) {
         ASSERT(forwardRange);
         return;
     }
 
-    BackwardsCharacterIterator backwardsIterator(makeRange(startOfDocument(visiblePosition), visiblePosition).get(), TextIteratorStopsOnFormControls);
+    // Same as with the forward range but with the backward range. The range
+    // starts at the document's start and ends at the selection start and will
+    // be updated.
+    RefPtrWillBeRawPtr<Range> backwardsRange = rangeOfContents(document);
+    backwardsRange->setEnd(position);
+    BackwardsCharacterIterator backwardsIterator(backwardsRange.get(), TextIteratorStopsOnFormControls);
     if (!backwardsIterator.atEnd())
         backwardsIterator.advance(halfMaxLength);
 
-    RefPtrWillBeRawPtr<Range> backwardsRange = backwardsIterator.range();
+    backwardsRange = backwardsIterator.range();
     if (!backwardsRange) {
         ASSERT(backwardsRange);
         return;
     }
 
     m_positionOffsetInContent = Range::create(*document, backwardsRange->endPosition(), position)->text().length();
     m_contentRange = Range::create(*document, backwardsRange->endPosition(), forwardRange->startPosition());
     ASSERT(m_contentRange);
 }
 
@@ skipping 26 matching lines @@
         return m_contentRange->text();
     return String();
 }
 
 unsigned SurroundingText::positionOffsetInContent() const
 {
     return m_positionOffsetInContent;
 }
 
 } // namespace WebCore