Constrain transform animation direct compositing reason to transforms.

third_party/WebKit/Source/core/paint/PaintPropertyTreeBuilderTest.cpp

 // Copyright 2015 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 "core/paint/PaintPropertyTreeBuilderTest.h"
 
 #include "core/html/HTMLIFrameElement.h"
 #include "core/layout/LayoutTreeAsText.h"
 #include "core/paint/ObjectPaintProperties.h"
 #include "core/paint/PaintPropertyTreePrinter.h"
@@ skipping 384 matching lines @@
 }
 
 TEST_P(PaintPropertyTreeBuilderTest,
        TransformNodeWithActiveAnimationHasDirectCompositingReason) {
   setBodyInnerHTML(
       "<style>"
       "@keyframes test {"
       "  0% { transform: translate(1em, 1em) } "
       "  100% { transform: translate(2em, 2em) } "
       "} "
+      ".animate { "
+      "  animation-name: test; "
+      "  animation-duration: 1s "
+      "}"
       "</style>"
-      "<div id='transform'"
-      "    style='animation-name: test; animation-duration: 1s'>"
-      "</div>");
+      "<div id='target' class='animate'></div>");
+  Element* target = document().getElementById("target");
+  const ObjectPaintProperties* properties =
+      target->layoutObject()->paintProperties();
+  EXPECT_TRUE(properties->transform()->hasDirectCompositingReasons());
+}
 
-  Element* transform = document().getElementById("transform");
-  const ObjectPaintProperties* transformProperties =
-      transform->layoutObject()->paintProperties();
-  EXPECT_TRUE(transformProperties->transform()->hasDirectCompositingReasons());
+TEST_P(PaintPropertyTreeBuilderTest,
+       OpacityAnimationDoesNotCreateTransformNode) {
+  setBodyInnerHTML(
+      "<style>"
+      "div {"
+      "  width: 100px;"
+      "  height: 100px;"
+      "  background-color: red;"
+      "  animation-name: example;"
+      "  animation-duration: 4s;"
+      "}"
+      "@keyframes example {"
+      "  from { opacity: 0.0;}"
+      "  to { opacity: 1.0;}"
+      "}"
+      "</style>"
+      "<div id='target'></div>");
+
+  Element* target = document().getElementById("target");
+  const ObjectPaintProperties* properties =
+      target->layoutObject()->paintProperties();
+  EXPECT_EQ(nullptr, properties->transform());
 }
 
 TEST_P(PaintPropertyTreeBuilderTest, WillChangeTransform) {
   setBodyInnerHTML(
       "<style> body { margin: 0 } </style>"
       "<div id='transform' style='margin-left: 50px; margin-top: 100px;"
       "    width: 400px; height: 300px;"
       "    will-change: transform'>"
       "</div>");
 
@@ skipping 2616 matching lines @@
   EXPECT_EQ(framePreTranslation(),
             childProperties->paintOffsetTranslation()->parent());
   EXPECT_EQ(childProperties->paintOffsetTranslation(),
             childPaintState.transform());
   // This will change once we added clip expansion node.
   EXPECT_EQ(filterProperties->effect()->outputClip(), childPaintState.clip());
   EXPECT_EQ(filterProperties->effect(), childPaintState.effect());
 }
 
 }  // namespace blink