[Editing][Regression] Contenteditable w/ "-webkit-user-select:all" should be editable for drag.

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

Index: third_party/WebKit/Source/core/editing/SelectionController.cpp
diff --git a/third_party/WebKit/Source/core/editing/SelectionController.cpp b/third_party/WebKit/Source/core/editing/SelectionController.cpp
index 425b435e967f5a104bc83d9f524fb73b2e5f1bcd..2fdc0254ca292344b5519e62dc6d45c709621e72 100644
--- a/third_party/WebKit/Source/core/editing/SelectionController.cpp
+++ b/third_party/WebKit/Source/core/editing/SelectionController.cpp
@@ -82,14 +82,23 @@ DispatchEventResult dispatchSelectStart(Node* node)
     return node->dispatchEvent(Event::createCancelableBubble(EventTypeNames::selectstart));
 }
 
-VisibleSelectionInFlatTree expandSelectionToRespectUserSelectAll(Node* targetNode, const VisibleSelectionInFlatTree& selection)
+static Node* rootUserSelectAllAndNotEditableNode(Node* const node)
 {
-    Node* rootUserSelectAll = EditingInFlatTreeStrategy::rootUserSelectAllForNode(targetNode);
+    Node* const rootUserSelectAll = EditingInFlatTreeStrategy::rootUserSelectAllForNode(node);

[yosin_UTC9, 2016/07/20 06:58:58]

As talked offline, we should have a function, usedValueOfUserSelect(element) to
compute used value of "user-select". 
We might be want to have usedValueOfUserSelect() in EditingUtilities.cpp or
VisbileUnit.cpp.

Once we have usedValueOfUserSelect(), SelectionControll doesn't need to check
user-modify.

[yoichio, 2016/07/27 02:27:21]

Created the function and use it in rootUserSelectAllForNode.

     if (!rootUserSelectAll)
-        return selection;
+        return nullptr;
     if (rootUserSelectAll->isHTMLElement() && toHTMLElement(rootUserSelectAll)->isTextFormControl())
-        return selection;
+        return nullptr;
     if (rootUserSelectAll->layoutObject()->style()->userModify() != READ_ONLY)
+        return nullptr;
+
+    return rootUserSelectAll;
+}
+
+VisibleSelectionInFlatTree expandSelectionToRespectUserSelectAll(Node* targetNode, const VisibleSelectionInFlatTree& selection)
+{
+    Node* const rootUserSelectAll = rootUserSelectAllAndNotEditableNode(targetNode);
+    if (!rootUserSelectAll)
         return selection;
 
     VisibleSelectionInFlatTree newSelection(selection);
@@ -237,8 +246,9 @@ void SelectionController::updateSelectionForMouseDrag(const HitTestResult& hitTe
 
     if (RuntimeEnabledFeatures::userSelectAllEnabled()) {
         // TODO(yosin) Should we use |Strategy::rootUserSelectAllForNode()|?
-        Node* rootUserSelectAllForMousePressNode = EditingInFlatTreeStrategy::rootUserSelectAllForNode(mousePressNode);
-        if (rootUserSelectAllForMousePressNode && rootUserSelectAllForMousePressNode == EditingInFlatTreeStrategy::rootUserSelectAllForNode(target)) {
+        Node* const rootUserSelectAllForMousePressNode = rootUserSelectAllAndNotEditableNode(mousePressNode);
+        Node* const rootUserSelectAllForTarget = rootUserSelectAllAndNotEditableNode(target);
+        if (rootUserSelectAllForMousePressNode && rootUserSelectAllForMousePressNode == rootUserSelectAllForTarget) {
             newSelection.setBase(mostBackwardCaretPosition(PositionInFlatTree::beforeNode(rootUserSelectAllForMousePressNode), CanCrossEditingBoundary));
             newSelection.setExtent(mostForwardCaretPosition(PositionInFlatTree::afterNode(rootUserSelectAllForMousePressNode), CanCrossEditingBoundary));
         } else {
@@ -250,7 +260,6 @@ void SelectionController::updateSelectionForMouseDrag(const HitTestResult& hitTe
                     newSelection.setBase(mostForwardCaretPosition(PositionInFlatTree::afterNode(rootUserSelectAllForMousePressNode), CanCrossEditingBoundary));
             }
 
-            Node* rootUserSelectAllForTarget = EditingInFlatTreeStrategy::rootUserSelectAllForNode(target);
             if (rootUserSelectAllForTarget && mousePressNode->layoutObject() && toPositionInFlatTree(target->layoutObject()->positionForPoint(hitTestResult.localPoint()).position()).compareTo(toPositionInFlatTree(mousePressNode->layoutObject()->positionForPoint(dragStartPos).position())) < 0)
                 newSelection.setExtent(mostBackwardCaretPosition(PositionInFlatTree::beforeNode(rootUserSelectAllForTarget), CanCrossEditingBoundary));
             else if (rootUserSelectAllForTarget && mousePressNode->layoutObject())