Revert of cc: Implement shared worker contexts.

cc/trees/layer_tree_host_unittest.cc

Index: cc/trees/layer_tree_host_unittest.cc
diff --git a/cc/trees/layer_tree_host_unittest.cc b/cc/trees/layer_tree_host_unittest.cc
index d43bc7b6fcf47dbdafc1a90bbf54a2d20d10f7de..588f9e48ce111fb9ee0566eea078daad34b1dec2 100644
--- a/cc/trees/layer_tree_host_unittest.cc
+++ b/cc/trees/layer_tree_host_unittest.cc
@@ -463,7 +463,7 @@
     explicit MockSetWorkerContextShouldAggressivelyFreeResourcesOutputSurface(
         bool delegated_rendering)
         : FakeOutputSurface(TestContextProvider::Create(),
-                            TestContextProvider::CreateWorker(),
+                            TestContextProvider::Create(),
                             delegated_rendering) {}
     MOCK_METHOD1(SetWorkerContextShouldAggressivelyFreeResources,
                  void(bool is_visible));
@@ -6174,21 +6174,5 @@
 
 MULTI_THREAD_TEST_F(LayerTreeHostScrollingAndScalingUpdatesLayers);
 
-class LayerTreeHostTestDestroyWhileInitializingOutputSurface
-    : public LayerTreeHostTest {
- protected:
-  void BeginTest() override {
-    // By ending the test immediately we start initialization of an output
-    // surface but destroy the LTH before it completes. This test verifies
-    // that this works correctly and the output surface is destroyed on
-    // the correct thread.
-    EndTest();
-  }
-
-  void AfterTest() override {}
-};
-
-MULTI_THREAD_TEST_F(LayerTreeHostTestDestroyWhileInitializingOutputSurface);
-
 }  // namespace
 }  // namespace cc