Cleanup GN BUILD files, gni's and imports.

mojo/mojo_application_package.gni

 # 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("//third_party/mojo/src/mojo/public/mojo_application.gni")
+import("//mojo/public/mojo_application.gni")
 
 # Used for mojo applications that have resources. This creates a directory
 # named output_name with the following contents:
 #   output_name.mojo : the shared library
 #   resources        : resources
 template("mojo_application_package") {
   mojo_deps = []
   if (defined(invoker.deps)) {
     mojo_deps += invoker.deps
   }
@@ skipping 88 matching lines @@
       public = invoker.public
     }
     if (defined(invoker.sources)) {
       sources = invoker.sources
     }
     if (defined(invoker.testonly)) {
       testonly = invoker.testonly
     }
   }
 }