Use invalidation sets for :-webkit-drag.

third_party/WebKit/Source/core/css/DragUpdateTest.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/dom/Element.h"
 #include "core/dom/StyleEngine.h"
 #include "core/frame/FrameView.h"
 #include "core/html/HTMLDocument.h"
 #include "core/html/HTMLElement.h"
@@ skipping 22 matching lines @@
     unsigned startCount = document.styleEngine().resolverAccessCount();
 
     document.documentElement()->layoutObject()->updateDragState(true);
     document.view()->updateAllLifecyclePhases();
 
     unsigned accessCount = document.styleEngine().resolverAccessCount() - startCount;
 
     ASSERT_EQ(1U, accessCount);
 }
 
-TEST(DragUpdateTest, ChildrenOrSiblingsAffectedByDragUpdate)
+TEST(DragUpdateTest, ChildAffectedByDragUpdate)
 {
     // Check that when dragging the div in the document below, you get a
-    // full subtree style recalc.
+    // single element style recalc.
 
     OwnPtr<DummyPageHolder> dummyPageHolder = DummyPageHolder::create(IntSize(800, 600));
     HTMLDocument& document = toHTMLDocument(dummyPageHolder->document());
-    document.documentElement()->setInnerHTML("<style>div {width:100px;height:100px} div:-webkit-drag span { background-color: green }</style>"
+    document.documentElement()->setInnerHTML("<style>div {width:100px;height:100px} div:-webkit-drag .drag { background-color: green }</style>"
         "<div>"
         "<span></span>"
         "<span></span>"
-        "<span></span>"
+        "<span class='drag'></span>"
         "<span></span>"
         "</div>", ASSERT_NO_EXCEPTION);
 
     document.updateLayout();
     unsigned startCount = document.styleEngine().resolverAccessCount();
 
     document.documentElement()->layoutObject()->updateDragState(true);
     document.updateLayout();
 
     unsigned accessCount = document.styleEngine().resolverAccessCount() - startCount;
 
-    ASSERT_EQ(5U, accessCount);
+    ASSERT_EQ(1U, accessCount);
+}
+
+TEST(DragUpdateTest, SiblingAffectedByDragUpdate)
+{
+    // Check that when dragging the div in the document below, you get a
+    // single element style recalc.
+
+    OwnPtr<DummyPageHolder> dummyPageHolder = DummyPageHolder::create(IntSize(800, 600));
+    HTMLDocument& document = toHTMLDocument(dummyPageHolder->document());
+    document.documentElement()->setInnerHTML("<style>div {width:100px;height:100px} div:-webkit-drag + .drag { background-color: green }</style>"
+        "<div>"
+        "<span></span>"
+        "<span></span>"
+        "<span></span>"
+        "<span></span>"
+        "</div>"
+        "<span class='drag'></span>", ASSERT_NO_EXCEPTION);
+
+    document.updateLayout();
+    unsigned startCount = document.styleEngine().resolverAccessCount();
+
+    document.documentElement()->layoutObject()->updateDragState(true);
+    document.updateLayout();
+
+    unsigned accessCount = document.styleEngine().resolverAccessCount() - startCount;
+
+    ASSERT_EQ(1U, accessCount);
 }
 
 } // namespace blink