Modify bindings to enforce that an error handler callback is only set after binding to a msg pipe.

mojo/public/cpp/bindings/lib/binding_state.h

 // Copyright 2015 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_LIB_BINDING_STATE_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDING_STATE_H_
 
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
@@ skipping 71 matching lines @@
   }
 
   InterfaceRequest<Interface> Unbind() {
     InterfaceRequest<Interface> request =
         MakeRequest<Interface>(router_->PassMessagePipe());
     DestroyRouter();
     return request.Pass();
   }
 
   void set_connection_error_handler(const Closure& error_handler) {
+    DCHECK(is_bound());
     connection_error_handler_ = error_handler;
   }
 
   Interface* impl() { return impl_; }
 
   bool is_bound() const { return !!router_; }
 
   MessagePipeHandle handle() const {
     DCHECK(is_bound());
     return router_->handle();
   }
 
   AssociatedGroup* associated_group() { return nullptr; }
 
   void EnableTestingMode() {
     DCHECK(is_bound());
     router_->EnableTestingMode();
   }
 
  private:
   void DestroyRouter() {
     router_->set_connection_error_handler(Closure());
     delete router_;
     router_ = nullptr;
+    connection_error_handler_.reset();
   }
 
   internal::Router* router_ = nullptr;
   typename Interface::Stub_ stub_;
   Interface* impl_;
   Closure connection_error_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(BindingState);
 };
 
@@ skipping 42 matching lines @@
       MojoDeadline deadline = MOJO_DEADLINE_INDEFINITE) {
     DCHECK(router_);
     return router_->WaitForIncomingMessage(deadline);
   }
 
   void Close() {
     DCHECK(router_);
     endpoint_client_.reset();
     router_->CloseMessagePipe();
     router_ = nullptr;
+    connection_error_handler_.reset();
   }
 
   InterfaceRequest<Interface> Unbind() {
     endpoint_client_.reset();
     InterfaceRequest<Interface> request =
         MakeRequest<Interface>(router_->PassMessagePipe());
     router_ = nullptr;
+    connection_error_handler_.reset();
     return request.Pass();
   }
 
   void set_connection_error_handler(const Closure& error_handler) {
+    DCHECK(is_bound());
     connection_error_handler_ = error_handler;
   }
 
   Interface* impl() { return impl_; }
 
   bool is_bound() const { return !!router_; }
 
   MessagePipeHandle handle() const {
     DCHECK(is_bound());
     return router_->handle();
@@ skipping 16 matching lines @@
   Interface* impl_;
   Closure connection_error_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(BindingState);
 };
 
 }  // namesapce internal
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDING_STATE_H_