Add gyp flag to specify whether we should optimize JNI generation.

build/jar_file_jni_generator.gypi

 # Copyright (c) 2012 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 file is meant to be included into a target to provide a rule
 # to generate jni bindings for system Java-files in a consistent manner.
 #
 # To use this, create a gyp target with the following form:
 # {
 #   'target_name': 'android_jar_jni_headers',
@@ skipping 24 matching lines @@
         '<(SHARED_INTERMEDIATE_DIR)/<(jni_gen_dir)/jni/<(java_class_name)_jni.h',
       ],
       'action': [
         '<(jni_generator)',
         '-j',
         '<(input_jar_file)',
         '--input_file',
         '<(input_java_class)',
         '--output_dir',
         '<(SHARED_INTERMEDIATE_DIR)/<(jni_gen_dir)/jni',
+        '--optimize_generation',
+        '<(optimize_jni_generation)',
       ],
       'message': 'Generating JNI bindings from  <(input_jar_file)/<(input_java_class)',
       'process_outputs_as_sources': 1,
     },
   ],
   # This target exports a hard dependency because it generates header
   # files.
   'hard_dependency': 1,
 }