cc: Fix hit-testing in zero-opacity layers.

cc/trees/occlusion_tracker_unittest.cc

Index: cc/trees/occlusion_tracker_unittest.cc
diff --git a/cc/trees/occlusion_tracker_unittest.cc b/cc/trees/occlusion_tracker_unittest.cc
index 0e8b5d4c50f3d2260735df92b8635f94d39b55d2..90f7fb4fd70db2790b77d6084b242fcf40eab4d4 100644
--- a/cc/trees/occlusion_tracker_unittest.cc
+++ b/cc/trees/occlusion_tracker_unittest.cc
@@ -4006,5 +4006,37 @@ class OcclusionTrackerTestEmptyEventLayerDoesNotOcclude
 
 ALL_OCCLUSIONTRACKER_TEST(OcclusionTrackerTestEmptyEventLayerDoesNotOcclude)
 
+template <class Types>
+class OcclusionTrackerTestZeroOpacityLayerDoesNotOcclude
+    : public OcclusionTrackerTest<Types> {
+ protected:
+  explicit OcclusionTrackerTestZeroOpacityLayerDoesNotOcclude(bool opaque)
+      : OcclusionTrackerTest<Types>(opaque) {}
+  void RunMyTest() {
+    typename Types::ContentLayerType* root = this->CreateRoot(
+        this->identity_matrix, gfx::Point(), gfx::Size(400, 400));
+    typename Types::ContentLayerType* zero_opacity_layer =
+        this->CreateDrawingLayer(root, this->identity_matrix, gfx::Point(),
+                                 gfx::Size(200, 200), true);
+    this->SetDrawsContent(zero_opacity_layer, false);
+    zero_opacity_layer->SetTouchEventHandlerRegion(gfx::Rect(10, 10, 10, 10));
+
+    this->CalcDrawEtc(root);
+
+    TestOcclusionTrackerWithClip<typename Types::LayerType,
+                                 typename Types::RenderSurfaceType> occlusion(
+        gfx::Rect(0, 0, 1000, 1000), false);
+
+    this->VisitLayer(zero_opacity_layer, &occlusion);
+
+    EXPECT_EQ(gfx::Rect().ToString(),
+              occlusion.occlusion_from_outside_target().ToString());
+    EXPECT_EQ(gfx::Rect().ToString(),
+              occlusion.occlusion_from_inside_target().ToString());
+  }
+};
+
+ALL_OCCLUSIONTRACKER_TEST(OcclusionTrackerTestZeroOpacityLayerDoesNotOcclude);
+
 }  // namespace
 }  // namespace cc