Add GN isolate support for a bunch of unittests.

cc/BUILD.gn

Index: cc/BUILD.gn
diff --git a/cc/BUILD.gn b/cc/BUILD.gn
index 52f114745ef41d89dd7dbe5285f76c2ea527bb89..1a241061a9da8521bc020a40145752b1f2d4ce56 100644
--- a/cc/BUILD.gn
+++ b/cc/BUILD.gn
@@ -696,6 +696,15 @@ source_set("test_support") {
   }
 }
 
+# TODO(GYP): Delete this after we've converted everything to GN.
+# The _run targets exist only for compatibility w/ GYP.
+group("cc_unittests_run") {
+  testonly = true
+  deps = [
+    ":cc_unittests",
+  ]
+}
+
 test("cc_unittests") {
   sources = [
     "animation/animation_host_unittest.cc",
@@ -835,6 +844,10 @@ test("cc_unittests") {
     "test/run_all_unittests.cc",
   ]
 
+  data = [
+    "test/data/",
+  ]
+
   deps = [
     ":cc",
     ":test_support",
@@ -855,6 +868,8 @@ test("cc_unittests") {
     "//ui/gl",
     "//ui/gl:test_support",
   ]
+
+  data_deps = [ "//third_party/mesa:osmesa" ]
 }
 
 test("cc_perftests") {