Add GN isolate support for a bunch of unittests.

ui/compositor/BUILD.gn

Index: ui/compositor/BUILD.gn
diff --git a/ui/compositor/BUILD.gn b/ui/compositor/BUILD.gn
index 283d1ab8a6c2b4f111f19ffde643d410a3a5d422..48b007bc4f7472c2c4616eb8c14810fdeac72dee 100644
--- a/ui/compositor/BUILD.gn
+++ b/ui/compositor/BUILD.gn
@@ -154,6 +154,15 @@ source_set("test_support") {
 }
 
 if (!is_android) {
+  # TODO(GYP): Delete this after we've converted everything to GN.
+  # The _run targets exist only for compatibility w/ GYP.
+  group("compositor_unittests_run") {
+    testonly = true
+    deps = [
+      ":compositor_unittests",
+    ]
+  }
+
   test("compositor_unittests") {
     sources = [
       "compositor_unittest.cc",
@@ -166,6 +175,10 @@ if (!is_android) {
       "transform_animation_curve_adapter_unittest.cc",
     ]
 
+    data = [
+      "//ui/gfx/test/data/compositor/",
+    ]
+
     deps = [
       ":compositor",
       ":test_support",