Allow touch adjustment to return Shadow DOM node.

LayoutTests/touchadjustment/resources/touchadjustment.js

Index: LayoutTests/touchadjustment/resources/touchadjustment.js
diff --git a/LayoutTests/touchadjustment/resources/touchadjustment.js b/LayoutTests/touchadjustment/resources/touchadjustment.js
index 2a3aa3d6716a82bb9f2589f1bbfbffadda3372e0..3b7ac5cf81d0330e5769a82303604d05d6528e50 100644
--- a/LayoutTests/touchadjustment/resources/touchadjustment.js
+++ b/LayoutTests/touchadjustment/resources/touchadjustment.js
@@ -63,9 +63,20 @@ function shouldBeWithin(adjustedPoint, targetArea) {
     }
 }
 
-function testTouchPoint(touchpoint, targetNode, allowTextNodes)
+function touchNodeAdjustedToBestClickableNode(left, top, width, height, doc, allowShadowDOM)
 {
-    var adjustedNode = internals.touchNodeAdjustedToBestClickableNode(touchpoint.left, touchpoint.top, touchpoint.width, touchpoint.height, document);
+    var adjustedNode = internals.touchNodeAdjustedToBestClickableNode(left, top, width, height, doc);
+    if (!allowShadowDOM && adjustedNode && adjustedNode.nodeType == 1) {

[Rick Byers, 2014/07/07 18:25:44]

There's probably only the one test that actually relies on adjusting into shadow
DOM.  Perhaps you can make this function ALWAYS allow shadow DOM (as the
internal API now does) and move the logic for properly testing the shadow cases
into the appropriate test cases?  Then you don't have to add this wrapper
function.

[Zeeshan Qureshi, 2014/07/09 16:10:14]

There's a couple of tests that do adjustment on <input> elements and the hit
test traverses into their shadow dom so this seems easier than updating them.

+        while (internals.shadowHost(adjustedNode)) {

[Rick Byers, 2014/07/07 18:25:44]

Rather than add shadowHost to internals, you should be able to get the same
thing by using the existing Element.shadowRoot and ShadowRoot.host (or maybe
olderShadowRoot) properties.  See
http://w3c.github.io/webcomponents/spec/shadow/#widl-Element-shadowRoot and
http://w3c.github.io/webcomponents/spec/shadow/#widl-ShadowRoot-host

[Zeeshan Qureshi, 2014/07/09 16:10:14]

Looks like this is for traversing down the tree.

[Rick Byers, 2014/07/09 19:46:58]

Ah right.  Still I think we can avoid adding a new Internals API for this
special case (each new Internals API has some maintenance burden - if the shadow
DOM folks haven't needed an API like this, then our case probably shouldn't
justify adding one).  You could ping esprehn to get his opinion - maybe there's
some existing API that we're missing.

If updating the existing tests is too painful then how about this:
 - find the root node for the returned node,
   - if it's type is DOCUMENT_FRAGEMENT_NODE then:
     - use document.querySelectorAll(input) to find all input nodes
     - compare the shadowRoot of each to see if it matches this
DOCUMENT_FRAGMENT_NODE
      - if so, use the input node as the result

This has the drawback of being specific to a single-level nesting of input, but
for the special case of touch adjustment testing (which really should just be
more shadow DOM aware) I think that's a better tradeoff than a new internals
API.  WDYT?

+            adjustedNode = internals.shadowHost(adjustedNode);
+        }
+    }
+    return adjustedNode;
+}
+
+function testTouchPoint(touchpoint, targetNode, allowTextNodes, allowShadowDOM)
+{
+    var adjustedNode = touchNodeAdjustedToBestClickableNode(touchpoint.left, touchpoint.top, touchpoint.width, touchpoint.height, document, allowShadowDOM);
     if (!allowTextNodes && adjustedNode && adjustedNode.nodeType == 3)
         adjustedNode = adjustedNode.parentNode;
     shouldBeNode(adjustedNode, targetNode);