Revert 265927 "Implement a trivial Mojo EchoService that can be ..."

> Implement a trivial Mojo EchoService that can be connected to over DBus
> 
> Some systems might like to use Mojo IPC to talk to services that are
> running outside the auspices of the Mojo shell. DBus is one potential
> channel to use for bootstrapping such a connection.
> 
> In order to allow the externally-running service to accept connections
> from a Mojo shell, we need to get it a ShellHandle. This change
> defines a DBusServiceLoader that implements the ServiceLoader
> interface.  DBusServiceLoader creates a dedicated MessagePipe, passes
> a handle to one end to the desired service over DBus, and then passes
> the ShellHandle over that pipe.
> 
> This class assumes the following:
> 1) Your service is already running,
> 2) Your service implements the Mojo ExternalService API
>    (from external_service.mojom).
> 3) Your service exports an object that implements the org.chromium.Mojo
>    DBus interface:
>    <interface name="org.chromium.Mojo">
>      <method name="ConnectChannel">
>        <arg type="h" name="file_descriptor" direction="in" />
>      </method>
>    </interface>
> 
> This change also includes a trivial DBusEchoService that can be
> "loaded" using the DBusServiceLoader, as well as a mojo example app
> that connects to this service.
> 
> BUG=364903
> TEST=run mojo_dbus_echo_service in one shell, and then load mojo_dbus_echo in the mojo shell. "who" should successfully echo between the two.
> 
> Review URL: https://codereview.chromium.org/242763003

TBR=cmasone@chromium.org

Review URL: https://codereview.chromium.org/253433003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@265935 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 0 insertions, 304 deletions

diff --git a/mojo/shell/DEPS b/mojo/shell/DEPS
index 7b96bb6..5cf2176 100644
--- a/mojo/shell/DEPS
+++ b/mojo/shell/DEPS
@@ -1,5 +1,4 @@
 include_rules = [
-  "+dbus",
   "+mojo/embedder",
   "+net",
   "+ui/gl",
diff --git a/mojo/shell/context.cc b/mojo/shell/context.cc
index d5bb30e..df86d14 100644
--- a/mojo/shell/context.cc
+++ b/mojo/shell/context.cc
@@ -5,7 +5,6 @@
 #include "mojo/shell/context.h"
 
 #include "base/command_line.h"
-#include "build/build_config.h"
 #include "mojo/embedder/embedder.h"
 #include "mojo/gles2/gles2_support_impl.h"
 #include "mojo/service_manager/service_loader.h"
@@ -18,10 +17,6 @@
 #include "mojo/shell/switches.h"
 #include "mojo/spy/spy.h"
 
-#if defined(OS_LINUX)
-#include "mojo/shell/dbus_service_loader_linux.h"
-#endif  // defined(OS_LINUX)
-
 namespace mojo {
 namespace shell {
 
@@ -71,12 +66,6 @@ Context::Context()
       scoped_ptr<ServiceLoader>(new NativeViewportServiceLoader(this)),
       GURL("mojo:mojo_native_viewport_service"));
 
-#if defined(OS_LINUX)
-  service_manager_.SetLoaderForScheme(
-      scoped_ptr<ServiceLoader>(new DBusServiceLoader(this)),
-      "dbus");
-#endif  // defined(OS_LINUX)
-
   if (cmdline->HasSwitch(switches::kSpy)) {
     spy_.reset(new mojo::Spy(&service_manager_,
                              cmdline->GetSwitchValueASCII(switches::kSpy)));
diff --git a/mojo/shell/dbus_service_loader_linux.cc b/mojo/shell/dbus_service_loader_linux.cc
deleted file mode 100644
index 496ccd3..0000000
--- a/mojo/shell/dbus_service_loader_linux.cc
+++ /dev/null
@@ -1,186 +0,0 @@
-// 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.
-
-#include "mojo/shell/dbus_service_loader_linux.h"
-
-#include <string>
-
-#include "base/command_line.h"
-#include "base/location.h"
-#include "base/logging.h"
-#include "base/task_runner_util.h"
-#include "base/threading/thread_restrictions.h"
-#include "dbus/bus.h"
-#include "dbus/file_descriptor.h"
-#include "dbus/message.h"
-#include "dbus/object_path.h"
-#include "dbus/object_proxy.h"
-#include "mojo/common/mojo_channel_init.h"
-#include "mojo/embedder/platform_channel_pair.h"
-#include "mojo/public/cpp/bindings/allocation_scope.h"
-#include "mojo/public/cpp/bindings/interface.h"
-#include "mojo/public/cpp/bindings/remote_ptr.h"
-#include "mojo/shell/context.h"
-#include "mojo/shell/external_service.mojom.h"
-#include "mojo/shell/keep_alive.h"
-
-namespace mojo {
-namespace shell {
-
-// Manages the connection to a single externally-running service.
-class DBusServiceLoader::LoadContext : public mojo::ExternalServiceHost {
- public:
-  // Kicks off the attempt to bootstrap a connection to the externally-running
-  // service specified by url_.
-  // Creates a MessagePipe and passes one end over DBus to the service. Then,
-  // calls ExternalService::Activate(ShellHandle) over the now-shared pipe.
-  LoadContext(DBusServiceLoader* loader,
-              const scoped_refptr<dbus::Bus>& bus,
-              const GURL& url,
-              ScopedShellHandle shell_handle)
-      : loader_(loader),
-        bus_(bus),
-        service_dbus_proxy_(NULL),
-        url_(url),
-        shell_handle_(shell_handle.Pass()),
-        keep_alive_(loader->context_) {
-    base::PostTaskAndReplyWithResult(
-        loader_->context_->task_runners()->io_runner(),
-        FROM_HERE,
-        base::Bind(&LoadContext::CreateChannelOnIOThread,
-                   base::Unretained(this)),
-        base::Bind(&LoadContext::ConnectChannel, base::Unretained(this)));
-  }
-
-  virtual ~LoadContext() {
-  }
-
- private:
-  // Sets up a pipe to share with the externally-running service and returns
-  // the endpoint that should be sent over DBus.
-  // The FD for the endpoint must be validated on an IO thread.
-  scoped_ptr<dbus::FileDescriptor> CreateChannelOnIOThread() {
-    base::ThreadRestrictions::AssertIOAllowed();
-    CHECK(bus_->Connect());
-    CHECK(bus_->SetUpAsyncOperations());
-
-    embedder::PlatformChannelPair channel_pair;
-    channel_init_.reset(new common::MojoChannelInit);
-    channel_init_->Init(
-        channel_pair.PassServerHandle().release().fd,
-        loader_->context_->task_runners()->io_runner());
-    CHECK(channel_init_->is_handle_valid());
-
-    scoped_ptr<dbus::FileDescriptor> client_fd(new dbus::FileDescriptor);
-    client_fd->PutValue(channel_pair.PassClientHandle().release().fd);
-    client_fd->CheckValidity();  // Must be run on an IO thread.
-    return client_fd.Pass();
-  }
-
-  // Sends client_fd over to the externally-running service. If that
-  // attempt is successful, the service will then be "activated" by
-  // sending it a ShellHandle.
-  void ConnectChannel(scoped_ptr<dbus::FileDescriptor> client_fd) {
-    size_t first_slash = url_.path().find_first_of('/');
-    DCHECK_NE(first_slash, std::string::npos);
-
-    const std::string service_name = url_.path().substr(0, first_slash);
-    const std::string object_path =  url_.path().substr(first_slash);
-    service_dbus_proxy_ =
-        bus_->GetObjectProxy(service_name, dbus::ObjectPath(object_path));
-
-    dbus::MethodCall call("org.chromium.Mojo", "ConnectChannel");
-    dbus::MessageWriter writer(&call);
-    writer.AppendFileDescriptor(*client_fd.get());
-
-    // TODO(cmasone): handle errors!
-    service_dbus_proxy_->CallMethod(
-        &call,
-        dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
-        base::Bind(&LoadContext::ActivateService, base::Unretained(this)));
-  }
-
-  // Sends a ShellHandle over to the now-connected externally-running service,
-  // using the Mojo ExternalService API.
-  void ActivateService(dbus::Response* response) {
-    mojo::ScopedExternalServiceHandle external_service_handle(
-        mojo::ExternalServiceHandle(
-            channel_init_->bootstrap_message_pipe().release().value()));
-    external_service_.reset(external_service_handle.Pass(), this);
-
-    mojo::AllocationScope scope;
-    external_service_->Activate(
-        mojo::ScopedMessagePipeHandle(
-            mojo::MessagePipeHandle(shell_handle_.release().value())));
-  }
-
-  // Should the ExternalService disappear completely, destroy connection state.
-  // NB: This triggers off of the service disappearing from
-  // DBus. Perhaps there's a way to watch at the Mojo layer instead,
-  // and that would be superior?
-  void HandleNameOwnerChanged(const std::string& old_owner,
-                              const std::string& new_owner) {
-    DCHECK(loader_->context_->task_runners()->ui_runner()->
-           BelongsToCurrentThread());
-
-    if (new_owner.empty()) {
-      loader_->context_->task_runners()->ui_runner()->PostTask(
-          FROM_HERE,
-          base::Bind(&DBusServiceLoader::ForgetService,
-                     base::Unretained(loader_), url_));
-    }
-  }
-
-  DBusServiceLoader* const loader_;
-  scoped_refptr<dbus::Bus> bus_;
-  dbus::ObjectProxy* service_dbus_proxy_;  // Owned by bus_;
-  const GURL url_;
-  ScopedShellHandle shell_handle_;
-  KeepAlive keep_alive_;
-  scoped_ptr<common::MojoChannelInit> channel_init_;
-  mojo::RemotePtr<mojo::ExternalService> external_service_;
-
-  DISALLOW_COPY_AND_ASSIGN(LoadContext);
-};
-
-DBusServiceLoader::DBusServiceLoader(Context* context) : context_(context) {
-  dbus::Bus::Options options;
-  options.bus_type = dbus::Bus::SESSION;
-  options.dbus_task_runner = context_->task_runners()->io_runner();
-  bus_ = new dbus::Bus(options);
-}
-
-DBusServiceLoader::~DBusServiceLoader() {
-  DCHECK(url_to_load_context_.empty());
-}
-
-void DBusServiceLoader::LoadService(ServiceManager* manager,
-                                    const GURL& url,
-                                    ScopedShellHandle service_handle) {
-  DCHECK(url.SchemeIs("dbus"));
-  DCHECK(url_to_load_context_.find(url) == url_to_load_context_.end());
-  url_to_load_context_[url] =
-      new LoadContext(this, bus_, url, service_handle.Pass());
-}
-
-void DBusServiceLoader::OnServiceError(ServiceManager* manager,
-                                       const GURL& url) {
-  // TODO(cmasone): Anything at all in this method here.
-}
-
-void DBusServiceLoader::ForgetService(const GURL& url) {
-  DCHECK(context_->task_runners()->ui_runner()->BelongsToCurrentThread());
-  DVLOG(2) << "Forgetting service (url: " << url << ")";
-
-  LoadContextMap::iterator it = url_to_load_context_.find(url);
-  DCHECK(it != url_to_load_context_.end()) << url;
-
-  LoadContext* doomed = it->second;
-  url_to_load_context_.erase(it);
-
-  delete doomed;
-}
-
-}  // namespace shell
-}  // namespace mojo
diff --git a/mojo/shell/dbus_service_loader_linux.h b/mojo/shell/dbus_service_loader_linux.h
deleted file mode 100644
index 8cb3f53..0000000
--- a/mojo/shell/dbus_service_loader_linux.h
+++ /dev/null
@@ -1,90 +0,0 @@
-// 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 MOJO_SHELL_DBUS_SERVICE_LOADER_H_
-#define MOJO_SHELL_DBUS_SERVICE_LOADER_H_
-
-#include <map>
-
-#include "base/macros.h"
-#include "base/memory/ref_counted.h"
-#include "mojo/public/cpp/system/core.h"
-#include "mojo/public/interfaces/shell/shell.mojom.h"
-#include "mojo/service_manager/service_loader.h"
-#include "mojo/shell/keep_alive.h"
-#include "url/gurl.h"
-
-namespace dbus {
-class Bus;
-}  // namespace dbus
-
-namespace mojo {
-namespace shell {
-
-class Context;
-
-// An implementation of ServiceLoader that contacts a system service
-// and bootstraps a Mojo connection to it over DBus.
-//
-// In order to allow the externally-running service to accept connections from
-// a Mojo shell, we need to get it a ShellHandle. This class creates a
-// dedicated MessagePipe, passes a handle to one end to the desired service
-// over DBus, and then passes the ShellHandle over that pipe.
-//
-// This class assumes the following:
-// 1) Your service is already running.
-// 2) Your service implements the Mojo ExternalService API
-//    (from external_service.mojom).
-// 3) Your service exports an object that implements the org.chromium.Mojo DBus
-//    interface:
-//    <interface name="org.chromium.Mojo">
-//      <method name="ConnectChannel">
-//        <arg type="h" name="file_descriptor" direction="in" />
-//      </method>
-//    </interface>
-class DBusServiceLoader : public ServiceLoader {
- public:
-  DBusServiceLoader(Context* context);
-  virtual ~DBusServiceLoader();
-
-  // URL for DBus services are of the following format:
-  // dbus:tld.domain.ServiceName/path/to/DBusObject
-  //
-  // This is simply the scheme (dbus:) and then the DBus service name followed
-  // by the DBus object path of an object that implements the org.chromium.Mojo
-  // interface as discussed above.
-  //
-  // Example:
-  //   dbus:org.chromium.EchoService/org/chromium/MojoImpl
-  //
-  // This will tell DBusServiceLoader to reach out to a service with
-  // the name "org.chromium.EchoService" and invoke the method
-  // "org.chromium.Mojo.ConnectChannel" on the object exported at
-  // "/org/chromium/MojoImpl".
-  virtual void LoadService(ServiceManager* manager,
-                           const GURL& url,
-                           ScopedShellHandle service_handle) OVERRIDE;
-
-  virtual void OnServiceError(ServiceManager* manager, const GURL& url)
-      OVERRIDE;
-
- private:
-  class LoadContext;
-
-  // Tosses out connection-related state to service at given URL.
-  void ForgetService(const GURL& url);
-
-  Context* const context_;
-  scoped_refptr<dbus::Bus> bus_;
-
-  typedef std::map<GURL, LoadContext*> LoadContextMap;
-  LoadContextMap url_to_load_context_;
-
-  DISALLOW_COPY_AND_ASSIGN(DBusServiceLoader);
-};
-
-}  // namespace shell
-}  // namespace mojo
-
-#endif  // MOJO_SHELL_DBUS_SERVICE_LOADER_H_
diff --git a/mojo/shell/external_service.mojom b/mojo/shell/external_service.mojom
deleted file mode 100644
index f76f5fe..0000000
--- a/mojo/shell/external_service.mojom
+++ /dev/null
@@ -1,16 +0,0 @@
-// 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.
-
-module mojo {
-
-[Peer=ExternalServiceHost]
-interface ExternalService {
-  Activate(handle<message_pipe> shell_handle);
-};
-
-[Peer=ExternalService]
-interface ExternalServiceHost {
-};
-
-}