Use invalidation sets for :-webkit-drag.

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

Index: third_party/WebKit/Source/core/css/DragUpdateTest.cpp
diff --git a/third_party/WebKit/Source/core/css/DragUpdateTest.cpp b/third_party/WebKit/Source/core/css/DragUpdateTest.cpp
index 63685dd69621b3c1294197aeacae222ea7737427..0cbe2869f5813b5c05e79d806a49d79ed6291ae7 100644
--- a/third_party/WebKit/Source/core/css/DragUpdateTest.cpp
+++ b/third_party/WebKit/Source/core/css/DragUpdateTest.cpp
@@ -40,18 +40,18 @@ TEST(DragUpdateTest, AffectedByDragUpdate)
     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);
 
@@ -63,7 +63,34 @@ TEST(DragUpdateTest, ChildrenOrSiblingsAffectedByDragUpdate)
 
     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