Remove the MessageLoop::DestructionObserver from mojo bindings.

mojo/public/cpp/bindings/strong_associated_binding.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_PUBLIC_CPP_BINDINGS_STRONG_ASSOCIATED_BINDING_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_STRONG_ASSOCIATED_BINDING_H_
 
 #include <memory>
 #include <string>
 #include <utility>
@@ skipping 11 matching lines @@
 namespace mojo {
 
 template <typename Interface>
 class StrongAssociatedBinding;
 
 template <typename Interface>
 using StrongAssociatedBindingPtr =
     base::WeakPtr<StrongAssociatedBinding<Interface>>;
 
 // This connects an interface implementation strongly to an associated pipe.
-// When a connection error is detected the implementation is deleted.
+// When a connection error is detected the implementation is deleted. If the
+// task runner that a StrongAssociatedBinding is bound on is stopped, the
+// connection error handler will not be invoked and the implementation will not
+// be deleted.
 //
 // To use, call StrongAssociatedBinding<T>::Create() (see below) or the helper
 // MakeStrongAssociatedBinding function:
 //
 //   mojo::MakeStrongAssociatedBinding(base::MakeUnique<FooImpl>(),
 //                                     std::move(foo_request));
 //
 template <typename Interface>
 class StrongAssociatedBinding {
  public:
@@ skipping 70 matching lines @@
 StrongAssociatedBindingPtr<Interface> MakeStrongAssociatedBinding(
     std::unique_ptr<Impl> impl,
     AssociatedInterfaceRequest<Interface> request) {
   return StrongAssociatedBinding<Interface>::Create(std::move(impl),
                                                     std::move(request));
 }
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_STRONG_ASSOCIATED_BINDING_H_