Add a full Blimp integration test.

blimp/client/support/compositor/BUILD.gn

Index: blimp/client/support/compositor/BUILD.gn
diff --git a/blimp/client/support/compositor/BUILD.gn b/blimp/client/support/compositor/BUILD.gn
index 829cd604e0336f012b189873628fa31c8267adce..36e14684b2de8eee9a7afc10823afec2ea239728 100644
--- a/blimp/client/support/compositor/BUILD.gn
+++ b/blimp/client/support/compositor/BUILD.gn
@@ -17,6 +17,8 @@ source_set("compositor") {
     "blimp_layer_tree_settings.h",
     "compositor_dependencies_impl.cc",
     "compositor_dependencies_impl.h",
+    "display_compositor.cc",
+    "display_compositor.h",
   ]
 
   public_deps = [
@@ -37,20 +39,3 @@ source_set("compositor") {
     "//ui/gfx:memory_buffer",
   ]
 }
-
-source_set("test_support") {
-  testonly = true
-
-  sources = [
-    "mock_compositor_dependencies.cc",
-    "mock_compositor_dependencies.h",
-  ]
-
-  deps = [
-    "//cc:test_support",
-  ]
-
-  public_deps = [
-    ":compositor",
-  ]
-}