Don't make :hover sticky on tap on sites that set a mobile viewport set

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index 5ef85b8c99b269694a820145e9b53603cb2d594f..264fb8d500a66c80f374fcd3a16b246e6e5020b2 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -3425,6 +3425,10 @@ void Document::styleResolverMayHaveChanged()
 
 void Document::setHoverNode(PassRefPtrWillBeRawPtr<Node> newHoverNode)
 {
+    if (!newHoverNode) {
+        m_hoverNode.clear();

[Rick Byers, 2014/11/17 22:00:10]

why is this change necessary?  Doesn't it already behave like this?  Eg. try
moving the mouse out of the window - that should call setHoverNode(nullptr)
already today I think.

+        return;
+    }
     m_hoverNode = newHoverNode;
 }
 
@@ -5424,10 +5428,21 @@ void Document::updateHoverActiveState(const HitTestRequest& request, Element* in
         }
     }
 
-    // Now set the hover state for our new object up to the root.
-    for (RenderObject* curr = newHoverObj; curr; curr = curr->hoverAncestor()) {
-        if (curr->node() && !curr->isText() && (!mustBeInActiveChain || curr->node()->inActiveChain()))
-            nodesToAddToChain.append(curr->node());
+    if ((settings() && settings()->viewportEnabled())

[Rick Byers, 2014/11/17 22:00:10]

The logic to decide when to apply this policy belongs in EventHandler, not here
in Document.  The behavior here should be based just on what HitTestRequest
flags are present.  This will be important, for example, when we start caching
HitTestResult objects keyed by their HitTestRequest.

+        && oldHoverObj == newHoverObj && request.touchEvent() && !request.active() && !request.hover()) {
+        // clear the :hover style after Tap, when meta viewport is set
+        for (RenderObject* curr = oldHoverObj; curr; curr = curr->hoverAncestor()) {

[Rick Byers, 2014/11/17 22:00:10]

please don't copy/paste code from above.  We should be able to refactor the code
to unify the "clear old hover" logic in one place.

+            if (curr->node() && !curr->isText() && (!mustBeInActiveChain || curr->node()->inActiveChain())) {
+                nodesToRemoveFromChain.append(curr->node());
+            }
+        }
+        setHoverNode(nullptr);
+    } else {
+        // Now set the hover state for our new object up to the root.
+        for (RenderObject* curr = newHoverObj; curr; curr = curr->hoverAncestor()) {
+            if (curr->node() && !curr->isText() && (!mustBeInActiveChain || curr->node()->inActiveChain()))
+                nodesToAddToChain.append(curr->node());
+        }
     }
 
     // mouseenter and mouseleave events do not bubble, so they are dispatched iff there is a capturing