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 376 matching lines @@
   transform->setAttribute(
       HTMLNames::styleAttr,
       "margin-left: 50px; margin-top: 100px; width: 400px; height: 300px; "
       "transform: translate3d(123px, 456px, 789px)");
   document().view()->updateAllLifecyclePhases();
   EXPECT_EQ(
       TransformationMatrix().translate3d(123, 456, 789),
       transform->layoutObject()->paintProperties()->transform()->matrix());
 }
 
+namespace {
+
+const char* kSimpleTransformAnimationHTML =
+    "<style>"
+    "@keyframes test {"
+    "  0% { transform: translate(1em, 1em) } "
+    "  100% { transform: translate(2em, 2em) } "
+    "} "
+    ".animate { "
+    "  animation-name: test; "
+    "  animation-duration: 1s "
+    "}"
+    "</style>"
+    "<div id='target' class='animate'></div>";
+
+}  // namespace
+
 TEST_P(PaintPropertyTreeBuilderTest,
        TransformNodeWithActiveAnimationHasDirectCompositingReason) {
+  setBodyInnerHTML(kSimpleTransformAnimationHTML);
+  Element* target = document().getElementById("target");
+  const ObjectPaintProperties* properties =
+      target->layoutObject()->paintProperties();
+  EXPECT_TRUE(properties->transform()->hasDirectCompositingReasons());
+}
+
+TEST_P(PaintPropertyTreeBuilderTest,
+       TransformNodeWithAnimationLosesNodeWhenAnimationRemoved) {

[pdr., 2016/12/21 19:00:06]

Nit: can you move this test to PaintPropertyTreeUpdateTests?

[wkorman, 2016/12/21 19:20:53]

Done.

+  setBodyInnerHTML(kSimpleTransformAnimationHTML);
+  Element* target = document().getElementById("target");
+  const ObjectPaintProperties* properties =
+      target->layoutObject()->paintProperties();
+  EXPECT_TRUE(properties->transform()->hasDirectCompositingReasons());
+
+  // Removing the animation should remove the transform node.
+  target->removeAttribute(HTMLNames::classAttr);
+  document().view()->updateAllLifecyclePhases();
+  EXPECT_EQ(nullptr, properties->transform());
+}
+
+TEST_P(PaintPropertyTreeBuilderTest,
+       OpacityAnimationDoesNotCreateTransformNode) {
   setBodyInnerHTML(
       "<style>"
-      "@keyframes test {"
-      "  0% { transform: translate(1em, 1em) } "
-      "  100% { transform: translate(2em, 2em) } "
-      "} "
+      "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='transform'"
-      "    style='animation-name: test; animation-duration: 1s'>"
-      "</div>");
+      "<div id='target'></div>");
 
-  Element* transform = document().getElementById("transform");
-  const ObjectPaintProperties* transformProperties =
-      transform->layoutObject()->paintProperties();
-  EXPECT_TRUE(transformProperties->transform()->hasDirectCompositingReasons());
+  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