Implement 'sequential focus navigation starting point.'

third_party/WebKit/Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 559 matching lines @@
 
 #if !ENABLE(OILPAN)
 void Document::dispose()
 {
     ASSERT_WITH_SECURITY_IMPLICATION(!m_deletionHasBegun);
 
     // We must make sure not to be retaining any of our children through
     // these extra pointers or we will create a reference cycle.
     m_docType = nullptr;
     m_focusedElement = nullptr;
+    m_sequentialFocusNavigationStartingPoint = nullptr;
     m_hoverNode = nullptr;
     m_activeHoverElement = nullptr;
     m_titleElement = nullptr;
     m_documentElement = nullptr;
     m_contextFeatures = ContextFeatures::defaultSwitch();
     m_userActionElements.documentDidRemoveLastRef();
     m_associatedFormControls.clear();
 
     m_scriptRunner->dispose();
     detachParser();
@@ skipping 1647 matching lines @@
     m_hoverNode = nullptr;
     m_activeHoverElement = nullptr;
     m_autofocusElement = nullptr;
 
     if (m_focusedElement.get()) {
         RefPtrWillBeRawPtr<Element> oldFocusedElement = m_focusedElement;
         m_focusedElement = nullptr;
         if (frameHost())
             frameHost()->chromeClient().focusedNodeChanged(oldFocusedElement.get(), nullptr);
     }
+    m_sequentialFocusNavigationStartingPoint = nullptr;
 
     if (this == &axObjectCacheOwner())
         clearAXObjectCache();
 
     m_layoutView = nullptr;
     ContainerNode::detach(context);
 
     if (this != &axObjectCacheOwner()) {
         if (AXObjectCache* cache = existingAXObjectCache()) {
             // Documents that are not a root document use the AXObjectCache in
@@ skipping 1368 matching lines @@
     if (newFocusedElement)
         updateLayoutTreeForNodeIfNeeded(newFocusedElement.get());
     if (newFocusedElement && newFocusedElement->isFocusable()) {
         if (newFocusedElement->isRootEditableElement() && !acceptsEditingFocus(*newFocusedElement)) {
             // delegate blocks focus change
             focusChangeBlocked = true;
             goto SetFocusedElementDone;
         }
         // Set focus on the new node
         m_focusedElement = newFocusedElement;
+        setSequentialFocusNavigationStartingPoint(m_focusedElement.get());
 
         m_focusedElement->setFocus(true);
         // Element::setFocus for frames can dispatch events.
         if (m_focusedElement != newFocusedElement) {
             focusChangeBlocked = true;
             goto SetFocusedElementDone;
         }
         cancelFocusAppearanceUpdate();
         m_focusedElement->updateFocusAppearance(params.selectionBehavior);
 
@@ skipping 63 matching lines @@
     if (LocalFrame* frame = this->frame())
         frame->selection().didChangeFocus();
     return !focusChangeBlocked;
 }
 
 void Document::clearFocusedElement()
 {
     setFocusedElement(nullptr, FocusParams(SelectionBehaviorOnFocus::None, WebFocusTypeNone, nullptr));
 }
 
+void Document::setSequentialFocusNavigationStartingPoint(Node* node)
+{
+    if (!node) {
+        m_sequentialFocusNavigationStartingPoint = nullptr;
+        return;
+    }
+    ASSERT(node->document() == this);
+    if (!m_sequentialFocusNavigationStartingPoint)
+        m_sequentialFocusNavigationStartingPoint = Range::create(*this);
+    m_sequentialFocusNavigationStartingPoint->selectNodeContents(node->isElementNode() ? node : node->parentOrShadowHostElement(), ASSERT_NO_EXCEPTION);
+}
+
+Element* Document::sequentialFocusNavigationStartingPoint(WebFocusType type) const
+{
+    if (m_focusedElement)
+        return m_focusedElement.get();
+    if (!m_sequentialFocusNavigationStartingPoint)
+        return nullptr;
+    if (!m_sequentialFocusNavigationStartingPoint->collapsed()) {
+        Node* node = m_sequentialFocusNavigationStartingPoint->startContainer();
+        ASSERT(node == m_sequentialFocusNavigationStartingPoint->endContainer());
+        return node->isElementNode() ? toElement(node) : node->parentOrShadowHostElement();
+    }
+
+    // Range::selectNodeContents didn't select contents because the element had
+    // no children.
+    if (m_sequentialFocusNavigationStartingPoint->startContainer()->isElementNode()
+        && !m_sequentialFocusNavigationStartingPoint->startContainer()->hasChildren()
+        && m_sequentialFocusNavigationStartingPoint->startOffset() == 0)
+        return toElement(m_sequentialFocusNavigationStartingPoint->startContainer());
+
+    // A node selected by Range::selectNodeContents was removed from the
+    // document tree.
+    if (Node* nextNode = m_sequentialFocusNavigationStartingPoint->firstNode()) {
+        if (type == WebFocusTypeForward)
+            return ElementTraversal::previous(*nextNode);
+        if (nextNode->isElementNode())
+            return toElement(nextNode);
+        return ElementTraversal::next(*nextNode);
+    }
+    return nullptr;
+}
+
 void Document::setCSSTarget(Element* newTarget)
 {
     if (m_cssTarget)
         m_cssTarget->pseudoStateChanged(CSSSelector::PseudoTarget);
     m_cssTarget = newTarget;
     if (m_cssTarget)
         m_cssTarget->pseudoStateChanged(CSSSelector::PseudoTarget);
 }
 
 void Document::registerNodeList(const LiveNodeListBase* list)
@@ skipping 2145 matching lines @@
 }
 
 DEFINE_TRACE(Document)
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_importsController);
     visitor->trace(m_docType);
     visitor->trace(m_implementation);
     visitor->trace(m_autofocusElement);
     visitor->trace(m_focusedElement);
+    visitor->trace(m_sequentialFocusNavigationStartingPoint);
     visitor->trace(m_hoverNode);
     visitor->trace(m_activeHoverElement);
     visitor->trace(m_documentElement);
     visitor->trace(m_titleElement);
     visitor->trace(m_axObjectCache);
     visitor->trace(m_markers);
     visitor->trace(m_cssTarget);
     visitor->trace(m_currentScriptStack);
     visitor->trace(m_scriptRunner);
     visitor->trace(m_listsInvalidatedAtDocument);
@@ skipping 52 matching lines @@
 #ifndef NDEBUG
 using namespace blink;
 void showLiveDocumentInstances()
 {
     Document::WeakDocumentSet& set = Document::liveDocumentSet();
     fprintf(stderr, "There are %u documents currently alive:\n", set.size());
     for (Document* document : set)
         fprintf(stderr, "- Document %p URL: %s\n", document, document->url().string().utf8().data());
 }
 #endif