Introduce EphemeralRange::nodes() helper to traverse over a range.

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

Index: third_party/WebKit/Source/core/editing/EditingStyle.cpp
diff --git a/third_party/WebKit/Source/core/editing/EditingStyle.cpp b/third_party/WebKit/Source/core/editing/EditingStyle.cpp
index 163cbfb17e46d3197edc3447aae00c755f919209..97eafe7b080c205cda674070257641a30292078f 100644
--- a/third_party/WebKit/Source/core/editing/EditingStyle.cpp
+++ b/third_party/WebKit/Source/core/editing/EditingStyle.cpp
@@ -1400,12 +1400,11 @@ WritingDirection EditingStyle::textDirectionForSelection(const VisibleSelection&
         end = mostBackwardCaretPosition(selection.end());
 
         DCHECK(end.document());
-        Node* pastLast = Range::create(*end.document(), position.parentAnchoredEquivalent(), end.parentAnchoredEquivalent())->pastLastNode();

[Andrey Kraynov, 2016/08/16 10:02:11]

This is an example how we can avoid creating Range objects now.

[yosin_UTC9, 2016/08/17 01:45:31]

ACK

We should avoid to use |Position::compouteContainerNode()| instead of
|Position::parentAnchoredEquivalenent()|.
However, we've not found an example for diff of |computeContainerNode()| and
|parentAnchoredEquivalenent()| yet.

-        for (Node* n = node; n && n != pastLast; n = NodeTraversal::next(*n)) {

[Andrey Kraynov, 2016/08/16 10:02:11]

I have a question about check |n && n != pastLast|.
My version of |inRange| currently uses TraversalNextIterator that won't check
for NULL objects returned from NodeTraversal::next.
Should I create and use special CheckedNextIterator instead of
TraversalNextIterator?
Is that check really makes sence?

[yosin_UTC9, 2016/08/17 01:45:31]

Please add |DCHECK(n)| just in case. |n| should not be |nullptr| in range.
What happened when we pass empty range to |inRange()|?

[Andrey Kraynov, 2016/08/17 09:58:15]

Done.
I expect no iterations in this case.
Added a test for it.

-            if (!n->isStyledElement())
+        for (Node& n : inRange(position.parentAnchoredEquivalent(), end.parentAnchoredEquivalent())) {
+            if (!n.isStyledElement())
                 continue;
 
-            CSSComputedStyleDeclaration* style = CSSComputedStyleDeclaration::create(n);
+            CSSComputedStyleDeclaration* style = CSSComputedStyleDeclaration::create(&n);
             const CSSValue* unicodeBidi = style->getPropertyCSSValue(CSSPropertyUnicodeBidi);
             if (!unicodeBidi || !unicodeBidi->isPrimitiveValue())
                 continue;