Add options validation code in WaitSetDispatcher::WaitSetAddImpl().

mojo/edk/system/wait_set_dispatcher.h

 // Copyright 2016 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.
 
 #ifndef MOJO_EDK_SYSTEM_WAIT_SET_DISPATCHER_H_
 #define MOJO_EDK_SYSTEM_WAIT_SET_DISPATCHER_H_
 
 #include "mojo/edk/system/dispatcher.h"
 #include "mojo/public/cpp/system/macros.h"
 
@@ skipping 19 matching lines @@
 
   // Validates and/or sets default options for |MojoCreateWaitSetOptions|. If
   // non-null, |in_options| must point to a struct of at least
   // |in_options->struct_size| bytes. |out_options| must point to a (current)
   // |MojoCreateWaitSetOptions| and will be entirely overwritten on success (it
   // may be partly overwritten on failure).
   static MojoResult ValidateCreateOptions(
       UserPointer<const MojoCreateWaitSetOptions> in_options,
       MojoCreateWaitSetOptions* out_options);
 
+  // Like |ValidateCreateOptions()|, but for |MojoWaitSetAddOptions|.
+  static MojoResult ValidateWaitSetAddOptions(
+      UserPointer<const MojoWaitSetAddOptions> in_options,
+      MojoWaitSetAddOptions* out_options);
+
   static util::RefPtr<WaitSetDispatcher> Create(
       const MojoCreateWaitSetOptions& /*validated_options*/) {
     return AdoptRef(new WaitSetDispatcher());
   }
 
   // |Dispatcher| public methods:
   Type GetType() const override;
   bool SupportsEntrypointClass(EntrypointClass entrypoint_class) const override;
 
  private:
@@ skipping 14 matching lines @@
                              UserPointer<MojoWaitSetResult> results,
                              UserPointer<uint32_t> max_results) override;
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(WaitSetDispatcher);
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_WAIT_SET_DISPATCHER_H_