Communicate MT changes to impl-only scroll offset animations

third_party/WebKit/Source/platform/scroll/ScrollAnimatorTest.cpp

Index: third_party/WebKit/Source/platform/scroll/ScrollAnimatorTest.cpp
diff --git a/third_party/WebKit/Source/platform/scroll/ScrollAnimatorTest.cpp b/third_party/WebKit/Source/platform/scroll/ScrollAnimatorTest.cpp
index 679f5a6e598f7cd7b292fba1d710d8fb06348147..7116bc797d9363eea635377ba762a69379e3b673 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollAnimatorTest.cpp
+++ b/third_party/WebKit/Source/platform/scroll/ScrollAnimatorTest.cpp
@@ -519,4 +519,33 @@ TEST(ScrollAnimatorTest, CancellingCompositorAnimation)
     ThreadHeap::collectAllGarbage();
 }
 
+// This test verifies that ImplOnlyAnimationUpdates get cleared once they're
+// pushed to compositor animation host.
+TEST(ScrollAnimatorTest, ImplOnlyAnimationUpdatesCleared)
+{
+    MockScrollableArea* scrollableArea = MockScrollableArea::create(true);
+    TestScrollAnimator* scrollAnimator = new TestScrollAnimator(scrollableArea, getMockedTime);
+
+    EXPECT_CALL(*scrollableArea, registerForAnimation()).Times(2);
+
+    EXPECT_EQ(scrollAnimator->m_runState, ScrollAnimatorCompositorCoordinator::RunState::Idle);
+    EXPECT_FALSE(scrollAnimator->hasAnimationThatRequiresService());
+    EXPECT_TRUE(scrollAnimator->m_implOnlyAnimationAdjustments.empty());
+
+    scrollAnimator->updateImplOnlyScrollOffsetAnimation(FloatSize(100.f, 100.f));
+    scrollAnimator->updateImplOnlyScrollOffsetAnimation(FloatSize(10.f, -10.f));
+
+    EXPECT_TRUE(scrollAnimator->hasAnimationThatRequiresService());
+    EXPECT_EQ(2U, scrollAnimator->m_implOnlyAnimationAdjustments.size());
+
+    scrollAnimator->updateCompositorAnimations();
+
+    EXPECT_EQ(scrollAnimator->m_runState, ScrollAnimatorCompositorCoordinator::RunState::Idle);
+    EXPECT_FALSE(scrollAnimator->hasAnimationThatRequiresService());
+    EXPECT_TRUE(scrollAnimator->m_implOnlyAnimationAdjustments.empty());
+
+    // Forced GC in order to finalize objects depending on the mock object.
+    ThreadHeap::collectAllGarbage();
+}
+
 } // namespace blink