Simplify mojo/application/public/cpp/BUILD.gn to call the target cpp instead of application.

mojo/application/public/cpp/BUILD.gn

Index: mojo/application/public/cpp/BUILD.gn
diff --git a/mojo/application/public/cpp/BUILD.gn b/mojo/application/public/cpp/BUILD.gn
index 796f615edc2c1ba58b6cbe990ee92c499cb282a1..3ae5f0f94e671633160c6655a592f2ff2bfea7e3 100644
--- a/mojo/application/public/cpp/BUILD.gn
+++ b/mojo/application/public/cpp/BUILD.gn
@@ -5,7 +5,7 @@
 import("//third_party/mojo/src/mojo/public/mojo_sdk.gni")
 
 # GYP version: mojo/mojo_base.gyp:mojo_application_base
-mojo_sdk_source_set("application") {
+mojo_sdk_source_set("cpp") {
   restrict_external_deps = false
   sources = [
     "application_connection.h",
@@ -45,7 +45,7 @@ mojo_sdk_source_set("standalone") {
   ]
 
   public_deps = [
-    ":application",
+    ":cpp",
   ]
 
   mojo_sdk_deps = [
@@ -63,7 +63,7 @@ mojo_sdk_source_set("test_support") {
   ]
 
   deps = [
-    ":application",
+    ":cpp",
     "//mojo/application/public/interfaces",
     "//testing/gtest",
   ]
@@ -87,7 +87,7 @@ mojo_sdk_source_set("test_support_standalone") {
   ]
 
   deps = [
-    ":application",
+    ":cpp",
     "//mojo/application/public/interfaces",
   ]