cc: Clean up iterator template to only take 1 parameter.

cc/trees/occlusion_tracker_perftest.cc

Index: cc/trees/occlusion_tracker_perftest.cc
diff --git a/cc/trees/occlusion_tracker_perftest.cc b/cc/trees/occlusion_tracker_perftest.cc
index 27123cd6e4b27515fa392999c06fbee584f11a38..f4a2fafcc298ef22d273c1919844906d9176809c 100644
--- a/cc/trees/occlusion_tracker_perftest.cc
+++ b/cc/trees/occlusion_tracker_perftest.cc
@@ -91,12 +91,8 @@ TEST_F(OcclusionTrackerPerfTest, UnoccludedContentRect_FullyOccluded) {
   ASSERT_EQ(1u, rsll.size());
   EXPECT_EQ(1u, rsll[0]->render_surface()->layer_list().size());
 
-  typedef LayerIterator<LayerImpl,
-                        LayerImpl::LayerListType,
-                        LayerImpl::RenderSurfaceType,
-                        LayerIteratorActions::FrontToBack> IteratorType;
-  IteratorType begin = IteratorType::Begin(&rsll);
-  IteratorType end = IteratorType::End(&rsll);
+  LayerIterator<LayerImpl> begin = LayerIterator<LayerImpl>::Begin(&rsll);
+  LayerIterator<LayerImpl> end = LayerIterator<LayerImpl>::End(&rsll);
 
   LayerIteratorPosition<LayerImpl> pos = begin;
 
@@ -170,12 +166,8 @@ TEST_F(OcclusionTrackerPerfTest, UnoccludedContentRect_10OpaqueLayers) {
   EXPECT_EQ(static_cast<size_t>(kNumOpaqueLayers),
             rsll[0]->render_surface()->layer_list().size());
 
-  typedef LayerIterator<LayerImpl,
-                        LayerImpl::LayerListType,
-                        LayerImpl::RenderSurfaceType,
-                        LayerIteratorActions::FrontToBack> IteratorType;
-  IteratorType begin = IteratorType::Begin(&rsll);
-  IteratorType end = IteratorType::End(&rsll);
+  LayerIterator<LayerImpl> begin = LayerIterator<LayerImpl>::Begin(&rsll);
+  LayerIterator<LayerImpl> end = LayerIterator<LayerImpl>::End(&rsll);
 
   // The opaque_layers add occlusion.
   for (int i = 0; i < kNumOpaqueLayers - 1; ++i) {