cc: Remove the LayerTreeHost abstraction.

cc/test/layer_tree_test.h

Index: cc/test/layer_tree_test.h
diff --git a/cc/test/layer_tree_test.h b/cc/test/layer_tree_test.h
index b9a509078e712c463de66f9ec42523fa3af8cce5..fbe9996f24703c1ed681c79c770b6ea5b723bea0 100644
--- a/cc/test/layer_tree_test.h
+++ b/cc/test/layer_tree_test.h
@@ -12,8 +12,8 @@
 #include "cc/test/test_hooks.h"
 #include "cc/test/test_task_graph_runner.h"
 #include "cc/trees/compositor_mode.h"
+#include "cc/trees/layer_tree_host.h"
 #include "cc/trees/layer_tree_host_impl.h"
-#include "cc/trees/layer_tree_host_in_process.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace cc {
@@ -122,7 +122,6 @@ class LayerTreeTest : public testing::Test, public TestHooks {
   bool TestEnded() const { return ended_; }
 
   LayerTreeHost* layer_tree_host();
-  LayerTreeHostInProcess* layer_tree_host_in_process();
   LayerTree* layer_tree() { return layer_tree_host()->GetLayerTree(); }
   SharedBitmapManager* shared_bitmap_manager() const {
     return shared_bitmap_manager_.get();
@@ -173,7 +172,6 @@ class LayerTreeTest : public testing::Test, public TestHooks {
   std::unique_ptr<LayerTreeHostClientForTesting> client_;
   std::unique_ptr<LayerTreeHost> layer_tree_host_;
   std::unique_ptr<AnimationHost> animation_host_;
-  LayerTreeHostInProcess* layer_tree_host_in_process_;
 
   bool beginning_ = false;
   bool end_when_begin_returns_ = false;