GN: Fix enable_incremental_javac never recompiling changes to .srcjars

build/android/gyp/javac.py

 #!/usr/bin/env python
 #
 # 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.
 
 import optparse
 import os
 import shutil
 import re
@@ skipping 191 matching lines @@
       pdb_path = options.jar_path + '.pdb'
       javac_cmd = _ConvertToJMakeArgs(javac_cmd, pdb_path)
       if srcjars:
         _FixTempPathsInIncrementalMetadata(pdb_path, temp_dir)
 
     if srcjars:
       java_dir = os.path.join(temp_dir, 'java')
       os.makedirs(java_dir)
       for srcjar in options.java_srcjars:
         if changed_paths:
-          changed_paths.update(changes.IterChangedSubpaths(srcjar))
+          changed_paths.update(os.path.join(java_dir, f)
+                               for f in changes.IterChangedSubpaths(srcjar))
         build_utils.ExtractAll(srcjar, path=java_dir, pattern='*.java')
       jar_srcs = build_utils.FindInDirectory(java_dir, '*.java')
       jar_srcs = _FilterJavaFiles(jar_srcs, options.javac_includes)
       java_files.extend(jar_srcs)
       if changed_paths:
         # Set the mtime of all sources to 0 since we use the absense of .class
         # files to tell jmake which files are stale.
         for path in jar_srcs:
           os.utime(path, (0, 0))
 
@@ skipping 214 matching lines @@
       options,
       input_paths=input_paths,
       input_strings=javac_cmd,
       output_paths=output_paths,
       force=force,
       pass_changes=True)
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))