Initial native keyboard proof of concept.

examples/keyboard_client/BUILD.gn

Index: examples/keyboard_client/BUILD.gn
diff --git a/examples/echo_terminal/BUILD.gn b/examples/keyboard_client/BUILD.gn
similarity index 53%
copy from examples/echo_terminal/BUILD.gn
copy to examples/keyboard_client/BUILD.gn
index 0da27dd87b75ebec5bc4bd577e424a665133160a..f8f7f3b2da9c4ad5ac6f3841f5bdaf20ce4c3e97 100644
--- a/examples/echo_terminal/BUILD.gn
+++ b/examples/keyboard_client/BUILD.gn
@@ -4,17 +4,14 @@
 
 import("//mojo/public/mojo_application.gni")
 
-mojo_native_application("echo_terminal") {
-  deps = [
-    "//base",
-    "//mojo/application",
-    "//mojo/common",
-    "//mojo/public/cpp/application",
-    "//mojo/public/cpp/system",
-    "//mojo/services/terminal/public/interfaces",
+mojo_native_application("keyboard_client") {
+  sources = [
+    "keyboard_client.cc",
   ]
 
-  sources = [
-    "main.cc",
+  deps = [
+    "//base",
+    "//mojo/public/cpp/application:standalone",
+    "//mojo/services/keyboard/public/interfaces",
   ]
 }