Mojo's WTF dependencies should be set correctly regardless the path depth

mojo/mojom_bindings_generator_explicit.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',
   ],
   'variables': {
     'variables': {
@@ skipping 14 matching lines @@
       ['mojom_variant=="none"', {
         'mojom_output_languages%': 'c++,javascript,java',
       }, {
         'mojom_output_languages%': 'c++',
       }],
       ['for_blink=="true"', {
         'mojom_generator_wtf_arg%': [
           '--for_blink',
         ],
         'wtf_dependencies%': [
-          'mojo_public.gyp:mojo_cpp_bindings_wtf_support',
-          '../third_party/WebKit/Source/wtf/wtf.gyp:wtf',
+          '<(DEPTH)/mojo/mojo_public.gyp:mojo_cpp_bindings_wtf_support',
+          '<(DEPTH)/third_party/WebKit/Source/wtf/wtf.gyp:wtf',
         ],
       }, {
         'mojom_generator_wtf_arg%': [],
         'wtf_dependencies%': [],
       }],
     ],
   },
   # Given mojom files as inputs, generate sources.  These sources will be
   # exported to another target (via dependent_settings) to be compiled.  This
   # keeps code generation separate from compilation, allowing the same sources
@@ skipping 104 matching lines @@
         ],
         'additional_input_paths': [
           '<@(mojom_bindings_generator_sources)',
           '<@(mojom_files)',
         ],
         'mojom_generated_sources': [ '<@(mojom_generated_outputs)' ],
       },
     }
   },
 }