Add unittests for the bugs found in previous CL.

third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.h

Index: third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.h
diff --git a/third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.h b/third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.h
index 38e955b6e0505711de55c10e8b3966bba580b735..55086370d8c028d60bf0a841521a0570166042f2 100644
--- a/third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.h
+++ b/third_party/WebKit/Source/platform/graphics/compositing/PaintArtifactCompositor.h
@@ -170,6 +170,8 @@ class PLATFORM_EXPORT PaintArtifactCompositor {
   FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
                            Merge2DTransform);
   FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
+                           MergeTransformOrigin);
+  FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
                            MergeClip);
   FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
                            MergeOpacity);
@@ -187,11 +189,15 @@ class PLATFORM_EXPORT PaintArtifactCompositor {
                            TwoClips);
   FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
                            TwoEffects);
+  FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
+                           TwoTransformsClipBetween);
 
   FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
                            PendingLayer);
   FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
                            PendingLayerWithGeometry);
+  FRIEND_TEST_ALL_PREFIXES(PaintArtifactCompositorTestWithPropertyTrees,
+                           PendingLayerKnownOpaque);
 };
 
 }  // namespace blink