Remove static thread pointers from CC

cc/layer_unittest.cc

Index: cc/layer_unittest.cc
diff --git a/cc/layer_unittest.cc b/cc/layer_unittest.cc
index f1a64e8279aaacbe11d6156008fc8322debba79b..8407eb10b68361330c7316da9166737e44435c85 100644
--- a/cc/layer_unittest.cc
+++ b/cc/layer_unittest.cc
@@ -12,6 +12,7 @@
 #include "cc/layer_tree_host.h"
 #include "cc/settings.h"
 #include "cc/single_thread_proxy.h"
+#include "cc/thread.h"
 #include "cc/test/fake_layer_tree_host_client.h"
 #include "cc/test/geometry_test_utils.h"
 #include "cc/test/test_common.h"
@@ -40,7 +41,7 @@ public:
     MockLayerImplTreeHost()
         : LayerTreeHost(&m_fakeClient, LayerTreeSettings())
     {
-        initialize();
+        initialize(scoped_ptr<Thread>(NULL));
     }
 
     MOCK_METHOD0(setNeedsCommit, void());
@@ -528,8 +529,6 @@ TEST_F(LayerTest, checkPropertyChangeCausesCorrectBehavior)
 
 TEST_F(LayerTest, verifyPushPropertiesAccumulatesUpdateRect)
 {
-    DebugScopedSetImplThread setImplThread;
-
     scoped_refptr<Layer> testLayer = Layer::create();
     scoped_ptr<LayerImpl> implLayer = LayerImpl::create(1);
 
@@ -555,7 +554,7 @@ public:
     {
         scoped_ptr<FakeLayerImplTreeHost> host(new FakeLayerImplTreeHost);
         // The initialize call will fail, since our client doesn't provide a valid GraphicsContext3D, but it doesn't matter in the tests that use this fake so ignore the return value.
-        host->initialize();
+        host->initialize(scoped_ptr<Thread>(NULL));
         return host.Pass();
     }