Add android_library template

BUILD.gn

 # Copyright (c) 2013 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.
 
 # This is the root build file for GN. GN will start processing by loading this
 # file, and recursively load all dependencies until all dependencies are either
 # resolved or known not to exist (which will cause the build to fail). So if
 # you add a new build file, there must be some path of dependencies from this
 # file to your new one or GN won't know about it.
 
@@ skipping 59 matching lines @@
       "//crypto",
       "//net",
       "//skia",
       "//third_party/libusb",
       "//third_party/WebKit/Source/wtf",  # TODO(brettw) re-enable for Android.
       "//tools/gn",
       "//ui/base:ui_base",
       "//ui/events",
       "//ui/gfx",
     ]
+
+    deps += [
+      "//third_party/jsr-305:jsr_305_javalib",
+      "//third_party/guava:guava_javalib",
+    ]
   }
 }