Avoid unnecessary copies of AccessibilityChildrenVector

Source/modules/accessibility/AXLayoutObject.cpp

 /*
 * Copyright (C) 2008 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 1922 matching lines @@
         if (role != TreeItemRole && role != StaticTextRole)
             return false;
     }
     return true;
 }
 
 void AXLayoutObject::ariaListboxSelectedChildren(AccessibilityChildrenVector& result)
 {
     bool isMulti = isMultiSelectable();
 
-    AccessibilityChildrenVector childObjects = children();
+    const AccessibilityChildrenVector& childObjects = children();
     unsigned childrenSize = childObjects.size();
     for (unsigned k = 0; k < childrenSize; ++k) {
         // Every child should have aria-role option, and if so, check for selected attribute/state.
         AXObject* child = childObjects[k].get();
         if (child->isSelected() && child->ariaRoleAttribute() == ListBoxOptionRole) {
             result.append(child);
             if (!isMulti)
                 return;
         }
     }
@@ skipping 70 matching lines @@
 
 AXObject* AXLayoutObject::accessibilityImageMapHitTest(HTMLAreaElement* area, const IntPoint& point) const
 {
     if (!area)
         return 0;
 
     AXObject* parent = axObjectCache()->getOrCreate(area->imageElement());
     if (!parent)
         return 0;
 
-    AXObject::AccessibilityChildrenVector children = parent->children();
+    const AccessibilityChildrenVector& children = parent->children();
     unsigned count = children.size();
     for (unsigned k = 0; k < count; ++k) {
         if (children[k]->elementRect().contains(point))
             return children[k].get();
     }
 
     return 0;
 }
 
 bool AXLayoutObject::layoutObjectIsObservable(LayoutObject* renderer) const
@@ skipping 128 matching lines @@
         return;
 
     // Iterate through all of the children, including those that may have already been added, and
     // try to insert hidden nodes in the correct place in the DOM order.
     unsigned insertionIndex = 0;
     for (Node* child = node->firstChild(); child; child = child->nextSibling()) {
         if (child->renderer()) {
             // Find out where the last layout sibling is located within m_children.
             AXObject* childObject = axObjectCache()->get(child->renderer());
             if (childObject && childObject->accessibilityIsIgnored()) {
-                AccessibilityChildrenVector children = childObject->children();
+                const AccessibilityChildrenVector& children = childObject->children();
                 if (children.size())
                     childObject = children.last().get();
                 else
                     childObject = 0;
             }
 
             if (childObject)
                 insertionIndex = m_children.find(childObject) + 1;
             continue;
         }
@@ skipping 89 matching lines @@
 
 void AXLayoutObject::addRemoteSVGChildren()
 {
     AXSVGRoot* root = remoteSVGRootElement();
     if (!root)
         return;
 
     root->setParent(this);
 
     if (root->accessibilityIsIgnored()) {
-        AccessibilityChildrenVector children = root->children();
+        const AccessibilityChildrenVector& children = root->children();
         unsigned length = children.size();
         for (unsigned i = 0; i < length; ++i)
             m_children.append(children[i]);
     } else {
         m_children.append(root);
     }
 }
 
 void AXLayoutObject::ariaSelectedRows(AccessibilityChildrenVector& result)
 {
@@ skipping 107 matching lines @@
         if (label && label->renderer()) {
             LayoutRect labelRect = axObjectCache()->getOrCreate(label)->elementRect();
             result.unite(labelRect);
         }
     }
 
     return result;
 }
 
 } // namespace blink