IDL: Add build target for IDL dictionary impl generation in core

Source/bindings/core/idl.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.
 
 import("//third_party/WebKit/Source/bindings/idl.gni")
 import("//third_party/WebKit/Source/core/core.gni")
 
 # Don't actually read idl.gypi since that just defines variables in terms of
 # others, which gypi_to_gn doesn't handle.
 
+core_testing_definition_idl_files =
+  core_testing_dictionary_idl_files +
+  webcore_testing_idl_files
+
 # IDL file lists; see: http://www.chromium.org/developers/web-idl-interfaces
 # Interface IDL files: generate individual bindings (includes testing)
 core_interface_idl_files =
   core_idl_files +
-  webcore_testing_idl_files +
+  core_testing_definition_idl_files +
   generated_webcore_testing_idl_files
 
 # Static IDL files
 core_static_interface_idl_files =
   core_idl_files +
-  webcore_testing_idl_files
+  core_testing_definition_idl_files
 core_static_dependency_idl_files =
   core_dependency_idl_files +
   webcore_testing_dependency_idl_files
 
 # Generated IDL files
 core_generated_interface_idl_files =
   generated_webcore_testing_idl_files  # interfaces
 core_generated_dependency_idl_files =
   # FIXME: Generate separate core_global_constructors_idls
   # http://crbug.com/358074
@@ skipping 17 matching lines @@
   core_generated_interface_idl_files +
   core_generated_dependency_idl_files
 
 # Dependency IDL files: don't generate individual bindings, but do process
 # in IDL dependency computation, and count as build dependencies
 # 'core_dependency_idl_files' is already used in Source/core, so avoid
 # collision
 core_all_dependency_idl_files =
   core_static_dependency_idl_files +
   core_generated_dependency_idl_files