Add a full Blimp integration test.

blimp/client/test/compositor/BUILD.gn

Index: blimp/client/test/compositor/BUILD.gn
diff --git a/blimp/client/support/BUILD.gn b/blimp/client/test/compositor/BUILD.gn
similarity index 52%
copy from blimp/client/support/BUILD.gn
copy to blimp/client/test/compositor/BUILD.gn
index 3ddaa16a3a0be1f3ca3c59125dd833d286b699d4..6e09d2a4cd68fa8aff363831cb80bb55aca4c4ef 100644
--- a/blimp/client/support/BUILD.gn
+++ b/blimp/client/test/compositor/BUILD.gn
@@ -2,16 +2,21 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-group("support") {
-  public_deps = [
-    "//blimp/client/support/compositor",
+source_set("compositor") {
+  testonly = true
+
+  sources = [
+    "mock_compositor_dependencies.cc",
+    "mock_compositor_dependencies.h",
+    "test_display_compositor.cc",
+    "test_display_compositor.h",
   ]
-}
 
-group("test_support") {
-  testonly = true
+  deps = [
+    "//cc:test_support",
+  ]
 
   public_deps = [
-    "//blimp/client/support/compositor:test_support",
+    "//blimp/client/support/compositor",
   ]
 }