Add a simple prototype "terminal" example.

examples/echo_terminal/BUILD.gn

-# Copyright 2014 The Chromium Authors. All rights reserved.
+# Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//mojo/public/mojo_application.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 
-mojo_native_application("tracing") {
-  sources = [
-    "main.cc",
-    "trace_data_sink.cc",
-    "trace_data_sink.h",
-  ]
-
+mojo_native_application("echo_terminal") {
   deps = [
     ":bindings",
     "//base",
     "//mojo/application",
     "//mojo/common",
     "//mojo/public/cpp/application",
     "//mojo/public/cpp/system",
   ]
+
+  sources = [
+    "main.cc",
+  ]
 }
 
 mojom("bindings") {
+  public_deps = [
+    "//services/files:bindings",
+  ]
+
   sources = [
-    "tracing.mojom",
+    "terminal_client.mojom",
   ]
 }