[mojo] Enable ServiceRegistryImpl to override remote services

content/common/mojo/service_registry_impl.h

 // 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.
 
 #ifndef CONTENT_COMMON_MOJO_SERVICE_REGISTRY_IMPL_H_
 #define CONTENT_COMMON_MOJO_SERVICE_REGISTRY_IMPL_H_
 
 #include <map>
 #include <queue>
 #include <string>
 #include <utility>
 
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
 #include "content/public/common/service_registry.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "mojo/public/cpp/system/core.h"
 #include "mojo/shell/public/interfaces/service_provider.mojom.h"
 
 namespace content {
 
 class CONTENT_EXPORT ServiceRegistryImpl
     : public ServiceRegistry,
       public NON_EXPORTED_BASE(mojo::ServiceProvider) {
  public:
+  using ServiceFactory = base::Callback<void(mojo::ScopedMessagePipeHandle)>;
+
   ServiceRegistryImpl();
   ~ServiceRegistryImpl() override;
 
   // Binds this ServiceProvider implementation to a message pipe endpoint.
   void Bind(mojo::InterfaceRequest<mojo::ServiceProvider> request);
 
   // Binds to a remote ServiceProvider. This will expose added services to the
   // remote ServiceProvider with the corresponding handle and enable
   // ConnectToRemoteService to provide access to services exposed by the remote
   // ServiceProvider.
   void BindRemoteServiceProvider(mojo::ServiceProviderPtr service_provider);
 
+  // Registers a local service factory to intercept ConnectToRemoteService
+  // requests instead of actually connecting to the remote registry. Used only
+  // for testing.
+  void AddServiceOverrideForTesting(const std::string& service_name,
+                                    const ServiceFactory& service_factory);
+
   // ServiceRegistry overrides.
   void AddService(const std::string& service_name,
-                  const base::Callback<void(mojo::ScopedMessagePipeHandle)>
-                      service_factory) override;
+                  const ServiceFactory service_factory) override;
   void RemoveService(const std::string& service_name) override;
   void ConnectToRemoteService(const base::StringPiece& service_name,
                               mojo::ScopedMessagePipeHandle handle) override;
 
   bool IsBound() const;
 
   base::WeakPtr<ServiceRegistry> GetWeakPtr();
 
  private:
   // mojo::ServiceProvider overrides.
   void ConnectToService(const mojo::String& name,
                         mojo::ScopedMessagePipeHandle client_handle) override;
 
   void OnConnectionError();
 
   mojo::Binding<mojo::ServiceProvider> binding_;
   mojo::ServiceProviderPtr remote_provider_;
 
-  std::map<std::string, base::Callback<void(mojo::ScopedMessagePipeHandle)> >
-      service_factories_;
+  std::map<std::string, ServiceFactory> service_factories_;
   std::queue<std::pair<std::string, mojo::MessagePipeHandle> >
       pending_connects_;
 
+  std::map<std::string, ServiceFactory> service_overrides_;
+
   base::WeakPtrFactory<ServiceRegistry> weak_factory_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_MOJO_SERVICE_REGISTRY_IMPL_H_