Fix the .../cpp/application:test_support target.

TBR=vardhan@google.com

Review URL: https://codereview.chromium.org/2253513003 .

Cr-Mirrored-From: https://github.com/domokit/mojo
Cr-Mirrored-Commit: 28f1b06f66e8586476f0df2a3e2eecf6330db3bf
diff --git a/cpp/application/BUILD.gn b/cpp/application/BUILD.gn
index 7013df1..4d3334a 100644
--- a/cpp/application/BUILD.gn
+++ b/cpp/application/BUILD.gn
@@ -55,8 +55,9 @@
     ":application",
   ]
 
+  mojo_sdk_public_deps = [ "mojo/public:gtest" ]
+
   mojo_sdk_deps = [
-    "mojo/public:gtest",
     "mojo/public/cpp/bindings",
     "mojo/public/cpp/environment",
     "mojo/public/cpp/system",