Use data_deps rather then deps for mojo_bindings.

build/secondary/tools/grit/grit_rule.gni

 # 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.
 
 # Instantiate grit. This will produce a script target to run grit, and a
 # static library that compiles the .cc files.
 #
 # Parameters
 #
 #   source (required)
@@ skipping 36 matching lines @@
 #   output_name (optiona)
 #       Provide an alternate base name for the generated files, like the .d
 #       files. Normally these are based on the target name and go in the
 #       output_dir, but if multiple targets with the same name end up in
 #       the same output_dir, they can collide.
 #
 #   use_qualified_include (optional)
 #       If set, output_dir is not added to include_dirs.
 #
 #   deps  (optional)
+#   data_deps  (optional)
 #   visibility  (optional)
 #       Normal meaning.
 #
 # Example
 #
 #   grit("my_resources") {
 #     # Source and outputs are required.
 #     source = "myfile.grd"
 #     outputs = [
 #       "foo_strings.h",
@@ skipping 339 matching lines @@
       # we want to keep the public "no visibility specified" default.
       visibility = target_visibility + invoker.visibility
     }
 
     deps = [
       "//tools/grit:grit_sources",
     ]
     if (defined(invoker.deps)) {
       deps += invoker.deps
     }
+    if (defined(invoker.data_deps)) {
+      data_deps = invoker.data_deps
+    }
   }
 
   # This is the thing that people actually link with, it must be named the
   # same as the argument the template was invoked with.
   source_set(target_name) {
     # Since we generate a file, we need to be run before the targets that
     # depend on us.
     sources = grit_outputs
 
     # Deps set on the template invocation will go on the grit script running
     # target rather than this library.
     deps = [
       ":$grit_custom_target",
     ]
     public_configs = [ ":$grit_config" ]
 
     if (defined(invoker.public_configs)) {
       public_configs += invoker.public_configs
     }
 
     if (defined(invoker.visibility)) {
       visibility = invoker.visibility
     }
     output_name = grit_output_name
   }
 }