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',

[cjhopman, 2015/02/26 02:15:36]

this could probably use a really short comment about why:

# The java output directory is deleted to ensure that the java library doesn't
try to compile stale files.

[Ken Rockot(use gerrit already), 2015/02/26 02:36:16]

Done.

+      '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 14 matching lines @@
     '<(SHARED_INTERMEDIATE_DIR)',
     '<(SHARED_INTERMEDIATE_DIR)/third_party/mojo/src',
   ],
   'direct_dependent_settings': {
     'include_dirs': [
       '<(DEPTH)',
       '<(DEPTH)/third_party/mojo/src',
       '<(SHARED_INTERMEDIATE_DIR)',
       '<(SHARED_INTERMEDIATE_DIR)/third_party/mojo/src',
     ],
     'variables': {

[cjhopman, 2015/02/26 02:15:37]

It looks like this gypi doesn't satisfy (1) from
https://code.google.com/p/chromium/issues/detail?id=461622#c8

it should have something like:

'additional_input_paths': [
  '<@(_sources)',  # or '<(stamp_filename)'
  '<@(mojom_bindings_generator_sources)',
]

I think that, without that, changing the mojom won't actually trigger rebuilding
the java library that it's a part of (it should be pretty easy to confirm that).

Actually, I think that gyp now supports depfiles for actions and so we should
use those for the gyp actions (they are already used when using the scripts from
gn) and remove the requirement that inputs need to be added here. I've filed
http://crbug.com/462075 for that.

[Ken Rockot(use gerrit already), 2015/02/26 02:36:16]

Ah yeah, you're right. I've added additional_input_sources for now, assuming
depfiles use will be addressed in some future CL(s).

       'generated_src_dirs': [
         '<(PRODUCT_DIR)/java_mojo/<(_target_name)/src',
       ],
     },
   },
   'hard_dependency': 1,
 }