Animation: Cancel same-property animations on compositor

Source/core/animation/CompositorAnimationsTestHelper.h

Index: Source/core/animation/CompositorAnimationsTestHelper.h
diff --git a/Source/core/animation/CompositorAnimationsTestHelper.h b/Source/core/animation/CompositorAnimationsTestHelper.h
index 7b4db7a973af284545cd7729c4f1d72ee7d3add3..31c0f09ab9561789275e1dfd63b48e9da0ed98b2 100644
--- a/Source/core/animation/CompositorAnimationsTestHelper.h
+++ b/Source/core/animation/CompositorAnimationsTestHelper.h
@@ -145,6 +145,12 @@ private:
         PlatformProxy(WebCompositorSupportMock** compositor) : m_compositor(compositor) { }
 
         virtual void cryptographicallyRandomValues(unsigned char* buffer, size_t length) { ASSERT_NOT_REACHED(); }
+        const unsigned char* getTraceCategoryEnabledFlag(const char* categoryName) override
+        {
+            static const unsigned char tracingIsDisabled = 0;
+            return &tracingIsDisabled;
+        }
+
     private:
         WebCompositorSupportMock** m_compositor;
         virtual WebCompositorSupport* compositorSupport() override { return *m_compositor; }