Fix mojom Java generator running on its own.

mojo/public/tools/bindings/generators/mojom_java_generator.py

 # Copyright 2014 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.
 
 """Generates java source files from a mojom.Module."""
 
 import argparse
 import ast
 import os
 import re
@@ skipping 413 matching lines @@
     if self.output_dir and args.java_output_directory:
       self.output_dir = os.path.join(args.java_output_directory,
                                      GetPackage(self.module).replace('.', '/'))
       if not os.path.exists(self.output_dir):
         try:
           os.makedirs(self.output_dir)
         except:
           # Ignore errors on directory creation.
           pass
 
+    # Keep this above the others as .GetStructs() changes the state of the
+    # module, annotating structs with required information.
+    for struct in self.GetStructs():
+      self.Write(self.GenerateStructSource(struct),
+                 '%s.java' % GetNameForElement(struct))
+
     for enum in self.module.enums:
       self.Write(self.GenerateEnumSource(enum),
                  '%s.java' % GetNameForElement(enum))
 
-    for struct in self.module.structs:
-      self.Write(self.GenerateStructSource(struct),
-                 '%s.java' % GetNameForElement(struct))
-
     for interface in self.module.interfaces:
       self.Write(self.GenerateInterfaceSource(interface),
                  '%s.java' % GetNameForElement(interface))
       self.Write(self.GenerateInterfaceInternalSource(interface),
                  '%s_Internal.java' % GetNameForElement(interface))
 
     if self.module.constants:
       self.Write(self.GenerateConstantsSource(self.module),
                  '%s.java' % GetConstantsMainEntityName(self.module))
 
   def GetJinjaParameters(self):
     return {
       'lstrip_blocks': True,
       'trim_blocks': True,
     }
 
   def GetGlobals(self):
     return {
       'namespace': self.module.namespace,
       'module': self.module,
     }