Fix stale mojom-generated Java problems with gyp builds

third_party/mojo/mojom_bindings_generator.gypi

 # Copyright 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.
 
 {
   'includes': [
     'mojom_bindings_generator_variables.gypi',
   ],
+  'actions': [
+    {
+      'variables': {
+        'java_out_dir': '<(PRODUCT_DIR)/java_mojo/<(_target_name)/src',
+        'stamp_filename': '<(PRODUCT_DIR)/java_mojo/<(_target_name)/<(_target_name).stamp',
+      },
+      'action_name': '<(_target_name)_mojom_bindings_stamp',
+      # The java output directory is deleted to ensure that the java library
+      # doesn't try to compile stale files.
+      'action': [
+        'python', '<(DEPTH)/build/rmdir_and_stamp.py',
+        '<(java_out_dir)',
+        '<(stamp_filename)',
+      ],
+      'inputs': [ '<@(_sources)' ],
+      'outputs': [ '<(stamp_filename)' ],
+    }
+  ],
   'rules': [
     {
       'rule_name': '<(_target_name)_mojom_bindings_generator',
       'extension': 'mojom',
       'variables': {
         'mojom_base_output_dir':
             '<!(python <(DEPTH)/build/inverse_depth.py <(DEPTH))',
         'java_out_dir': '<(PRODUCT_DIR)/java_mojo/<(_target_name)/src',
         'mojom_import_args%': [
          '-I<(DEPTH)',
          '-I<(DEPTH)/third_party/mojo/src'
         ],
+        'stamp_filename': '<(PRODUCT_DIR)/java_mojo/<(_target_name)/<(_target_name).stamp',
       },
       'inputs': [
         '<@(mojom_bindings_generator_sources)',
+        '<(stamp_filename)',
       ],
       'outputs': [
         '<(SHARED_INTERMEDIATE_DIR)/<(mojom_base_output_dir)/<(RULE_INPUT_DIRNAME)/<(RULE_INPUT_ROOT).mojom.cc',
         '<(SHARED_INTERMEDIATE_DIR)/<(mojom_base_output_dir)/<(RULE_INPUT_DIRNAME)/<(RULE_INPUT_ROOT).mojom.h',
         '<(SHARED_INTERMEDIATE_DIR)/<(mojom_base_output_dir)/<(RULE_INPUT_DIRNAME)/<(RULE_INPUT_ROOT).mojom.js',
         '<(SHARED_INTERMEDIATE_DIR)/<(mojom_base_output_dir)/<(RULE_INPUT_DIRNAME)/<(RULE_INPUT_ROOT)_mojom.py',
         '<(SHARED_INTERMEDIATE_DIR)/<(mojom_base_output_dir)/<(RULE_INPUT_DIRNAME)/<(RULE_INPUT_ROOT).mojom-internal.h',
       ],
       'action': [
         'python', '<@(mojom_bindings_generator)',
@@ skipping 18 matching lines @@
     'include_dirs': [
       '<(DEPTH)',
       '<(DEPTH)/third_party/mojo/src',
       '<(SHARED_INTERMEDIATE_DIR)',
       '<(SHARED_INTERMEDIATE_DIR)/third_party/mojo/src',
     ],
     'variables': {
       'generated_src_dirs': [
         '<(PRODUCT_DIR)/java_mojo/<(_target_name)/src',
       ],
+      'additional_input_paths': [
+        '<@(mojom_bindings_generator_sources)',
+        '<@(_sources)',
+      ],
     },
   },
   'hard_dependency': 1,
 }