Add WebIDL compliant parser plus tests

tools/idl_parser/test_parser/implements.idl

+/* Copyright (c) 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. */
+
+/* Test Implements productions
+
+Run with --test to generate an AST and verify that all comments accurately
+reflect the state of the Nodes.
+
+BUILD Type(Name)
+This comment signals that a node of type <Type> is created with the
+name <Name>.
+
+ERROR Error String
+This comment signals that a error of <Error String> is generated.  The error
+is not assigned to a node, but are expected in order.
+
+PROP Key=Value
+This comment signals that a property has been set on the Node such that
+<Key> = <Value>.
+
+TREE
+Type(Name)
+  Type(Name)
+  Type(Name)
+    Type(Name)
+    ...
+This comment signals that a tree of nodes matching the BUILD comment
+symatics should exist.  This is an exact match.
+*/
+
+/* BUILD Implements(A) */
+/* PROP REFERENCE=B */
+A implements B;
+
+/* ERROR Unexpected ";" after keyword "implements". */
+A implements;
+
+/* BUILD Implements(B) */
+/* PROP REFERENCE=C */
+B implements C;
+
+/* ERROR Unexpected keyword "implements" after "]". */
+[foo] implements B;
+
+/* BUILD Implements(D) */
+/* PROP REFERENCE=E */
+D implements E;
+
+/* ERROR Unexpected keyword "implements" after comment. */
+implements C;
+