Constrain transform animation direct compositing reason to transforms.

third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinderTest.cpp

Index: third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinderTest.cpp
diff --git a/third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinderTest.cpp b/third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinderTest.cpp
index e4413f3085978014307c825c4b7ddd625fe09be4..0945dd32694c5bbc99e6f8e6707b0ef4d611e6f9 100644
--- a/third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinderTest.cpp
+++ b/third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinderTest.cpp
@@ -159,4 +159,56 @@ TEST_F(CompositingReasonFinderTest, OnlyOpaqueFixedLayersPromoted) {
   ASSERT_TRUE(paintLayer);
   EXPECT_EQ(NotComposited, paintLayer->compositingState());
 }
+
+TEST_F(CompositingReasonFinderTest, RequiresCompositingForTransformAnimation) {
+  RefPtr<ComputedStyle> style = ComputedStyle::create();
+  style->setSubtreeWillChangeContents(false);
+
+  style->setHasCurrentTransformAnimation(false);
+  style->setIsRunningTransformAnimationOnCompositor(false);
+  EXPECT_FALSE(
+      CompositingReasonFinder::requiresCompositingForTransformAnimation(
+          *style));
+
+  style->setHasCurrentTransformAnimation(false);
+  style->setIsRunningTransformAnimationOnCompositor(true);
+  EXPECT_FALSE(
+      CompositingReasonFinder::requiresCompositingForTransformAnimation(
+          *style));
+
+  style->setHasCurrentTransformAnimation(true);
+  style->setIsRunningTransformAnimationOnCompositor(false);
+  EXPECT_TRUE(CompositingReasonFinder::requiresCompositingForTransformAnimation(
+      *style));
+
+  style->setHasCurrentTransformAnimation(true);
+  style->setIsRunningTransformAnimationOnCompositor(true);
+  EXPECT_TRUE(CompositingReasonFinder::requiresCompositingForTransformAnimation(
+      *style));
+
+  style->setSubtreeWillChangeContents(true);
+
+  style->setHasCurrentTransformAnimation(false);
+  style->setIsRunningTransformAnimationOnCompositor(false);
+  EXPECT_FALSE(
+      CompositingReasonFinder::requiresCompositingForTransformAnimation(
+          *style));
+
+  style->setHasCurrentTransformAnimation(false);
+  style->setIsRunningTransformAnimationOnCompositor(true);
+  EXPECT_TRUE(CompositingReasonFinder::requiresCompositingForTransformAnimation(
+      *style));
+
+  style->setHasCurrentTransformAnimation(true);
+  style->setIsRunningTransformAnimationOnCompositor(false);
+  EXPECT_FALSE(
+      CompositingReasonFinder::requiresCompositingForTransformAnimation(
+          *style));
+
+  style->setHasCurrentTransformAnimation(true);
+  style->setIsRunningTransformAnimationOnCompositor(true);
+  EXPECT_TRUE(CompositingReasonFinder::requiresCompositingForTransformAnimation(
+      *style));
 }
+
+}  // namespace blink