Use correct offset when attribute auto is present

Source/core/dom/Position.cpp

Index: Source/core/dom/Position.cpp
diff --git a/Source/core/dom/Position.cpp b/Source/core/dom/Position.cpp
index dacff4069ead02e8d5f39e0d2d15bf0d9294ea25..fba587d1ee3cf603ff064bdf5d663f6140f16eca 100644
--- a/Source/core/dom/Position.cpp
+++ b/Source/core/dom/Position.cpp
@@ -79,6 +79,14 @@ static Node* previousRenderedEditable(Node* node)
     return 0;
 }
 
+static bool hasDirectionAutoAttribute(Node* node)
+{
+    bool isAuto = node->selfOrAncestorHasDirAutoAttribute();
+    if (node->isInShadowTree())
+        isAuto = equalIgnoringCase(node->shadowHost()->fastGetAttribute(dirAttr), "auto");

[leviw_travelin_and_unemployed, 2014/06/02 18:00:29]

This seems specific to TextArea. If you're inside arbitrary Shadow DOM content,
you may not want this. At a minimum, it seems like if isAuto is true before this
line, the lack of this attribute on the shadowHost shouldn't blow it away, so
maybe you want if (!isAuto node->isInShadowTree())?

Or perhaps we should already be propagating the
selfOrAncestorHasDirAutoAttribute across shadow boundaries? I'd love to hear
from some of our shadow DOM experts.

[esprehn, 2014/06/02 18:06:13]

I don't think this is correct, what if you're multiple levels down?

[Habib Virji, 2014/06/03 16:35:57]

@levi: If I get some assistance about how to find information about shadow
elements in setHasDirAutoFlagRecursively, it will help in setting correct values
for selfOrAncestorHasDirAutoAttribute.  

I have upload a new patch which tries to return early to address above issue,
instead of checking shadowtree node. 

[Habib Virji, 2014/06/03 16:35:57]

@esprehn: i have upload a new patch which check multiple down, if dir auto
attribute is set. It is similar to approach in setHasDirAutoFlagRecursively but
instead looking for shadow nodes. 

+    return isAuto;
+}
+
 Position::Position(PassRefPtrWillBeRawPtr<Node> anchorNode, LegacyEditingOffset offset)
     : m_anchorNode(anchorNode)
     , m_offset(offset.value())
@@ -1260,7 +1268,10 @@ void Position::getInlineBoxAndOffset(EAffinity affinity, TextDirection primaryDi
                     break;
                 inlineBox = prevBox;
             }
-            caretOffset = inlineBox->caretLeftmostOffset();
+            if (hasDirectionAutoAttribute(m_anchorNode.get()))
+                caretOffset = (inlineBox->bidiLevel() < level) ? inlineBox->caretLeftmostOffset() : inlineBox->caretRightmostOffset();
+            else
+                caretOffset = inlineBox->caretLeftmostOffset();
         } else if (nextBox->bidiLevel() > level) {
             // Left edge of a "tertiary" run. Set to the right edge of that run.
             while (InlineBox* tertiaryBox = inlineBox->nextLeafChildIgnoringLineBreak()) {