[remoting][linux host][open url] Update host for the new UX

This CL changes some host code to make the new open URL UX work.
Basically:

1. Introduce a new url-forwarder-config data channel for querying and
   configuring the URL forwarder, and the corresponding
   UrlForwarderConfigMessageHandler for handling it.
2. Replace ScopedUrlForwarder with a UrlForwarderConfigurator singleton.
3. Remove default browser restoring logic from the daemon script and the
   RemoteOpenUrl, since we don't do auto-restoring any more.
4. Rename setup_url_forwarder.py to configure_url_forwarder.py so that
   we don't need to strangely call "setup-url-forwarder --setup".

Bug: b:183135000
Change-Id: I26c77bbdf67d95608532e250656e176796df77eb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2946788
Commit-Queue: Yuwei Huang <yuweih@chromium.org>
Reviewed-by: Joe Downing <joedow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#892728}

remoting/host/BUILD.gn

@@ -324,8 +324,6 @@ static_library("common") {
     "resizing_host_observer.h",
     "resources.h",
     "sas_injector.h",
-    "scoped_url_forwarder.cc",
-    "scoped_url_forwarder.h",
     "screen_controls.h",
     "screen_resolution.cc",
     "screen_resolution.h",
@@ -343,6 +341,10 @@ static_library("common") {
     "token_validator_base.h",
     "token_validator_factory_impl.cc",
     "token_validator_factory_impl.h",
+    "url_forwarder_configurator.cc",
+    "url_forwarder_configurator.h",
+    "url_forwarder_control_message_handler.cc",
+    "url_forwarder_control_message_handler.h",
     "usage_stats_consent.h",
     "xmpp_register_support_host_request.cc",
     "xmpp_register_support_host_request.h",
@@ -476,8 +478,8 @@ static_library("common") {
       "curtain_mode_linux.cc",
       "disconnect_window_linux.cc",
       "keyboard_layout_monitor_linux.cc",
-      "scoped_url_forwarder_linux.cc",
-      "scoped_url_forwarder_linux.h",
+      "url_forwarder_configurator_linux.cc",
+      "url_forwarder_configurator_linux.h",
       "xsession_chooser_linux.cc",
     ]
   }

remoting/host/client_session.cc

@@ -32,6 +32,7 @@
 #include "remoting/host/remote_open_url_message_handler.h"
 #include "remoting/host/screen_controls.h"
 #include "remoting/host/screen_resolution.h"
+#include "remoting/host/url_forwarder_control_message_handler.h"
 #include "remoting/proto/control.pb.h"
 #include "remoting/proto/event.pb.h"
 #include "remoting/protocol/audio_stream.h"
@@ -206,6 +207,11 @@ void ClientSession::SetCapabilities(
         kRemoteOpenUrlDataChannelName,
         base::BindRepeating(&ClientSession::CreateRemoteOpenUrlMessageHandler,
                             base::Unretained(this)));
+    data_channel_manager_.RegisterCreateHandlerCallback(
+        UrlForwarderControlMessageHandler::kDataChannelName,
+        base::BindRepeating(
+            &ClientSession::CreateUrlForwarderControlMessageHandler,
+            base::Unretained(this)));
   }
 
   std::vector<ActionRequest::Action> supported_actions;
@@ -897,4 +903,13 @@ void ClientSession::CreateRemoteOpenUrlMessageHandler(
   new RemoteOpenUrlMessageHandler(channel_name, std::move(pipe));
 }
 
+void ClientSession::CreateUrlForwarderControlMessageHandler(
+    const std::string& channel_name,
+    std::unique_ptr<protocol::MessagePipe> pipe) {
+  // UrlForwarderControlMessageHandler manages its own lifetime and is tied to
+  // the lifetime of |pipe|. Once |pipe| is closed, this instance will be
+  // cleaned up.
+  new UrlForwarderControlMessageHandler(channel_name, std::move(pipe));
+}
+
 }  // namespace remoting

remoting/host/client_session.h

@@ -211,6 +211,10 @@ class ClientSession : public protocol::HostStub,
       const std::string& channel_name,
       std::unique_ptr<protocol::MessagePipe> pipe);
 
+  void CreateUrlForwarderControlMessageHandler(
+      const std::string& channel_name,
+      std::unique_ptr<protocol::MessagePipe> pipe);
+
   EventHandler* event_handler_;
 
   // Used to create a DesktopEnvironment instance for this session.

remoting/host/installer/linux/Makefile

@@ -49,8 +49,8 @@ install:
 	  "$(INSTALL_DIR)"
 	install "$(SRC_DIR)/remoting/host/installer/linux/Xsession" \
 	  "$(INSTALL_DIR)"
-	install "$(SRC_DIR)/remoting/host/linux/setup_url_forwarder.py" \
-	  "$(INSTALL_DIR)/setup-url-forwarder"
+	install "$(SRC_DIR)/remoting/host/linux/configure_url_forwarder.py" \
+	  "$(INSTALL_DIR)/configure-url-forwarder"
 
 	install -m 0644 \
 	  "$(BUILD_DIR)/remoting/com.google.chrome.remote_desktop.json" \

remoting/host/linux/BUILD.gn

@@ -59,7 +59,7 @@ if (enable_me2me_host) {
   }
 
   copy("remoting_me2me_host_copy_setup_url_forwarder_script") {
-    sources = [ "setup_url_forwarder.py" ]
+    sources = [ "configure_url_forwarder.py" ]
     outputs = [ "$root_build_dir/remoting/setup-url-forwarder" ]
   }
 

remoting/host/linux/linux_me2me_host.py

@@ -95,8 +95,6 @@
 
 USER_SESSION_PATH = os.path.join(SCRIPT_DIR, "user-session")
 
-SETUP_URL_FORWARDER_PATH = os.path.join(SCRIPT_DIR, "setup-url-forwarder")
-
 CHROME_REMOTING_GROUP_NAME = "chrome-remote-desktop"
 
 HOME_DIR = os.environ["HOME"]
@@ -827,21 +825,6 @@ def sigusr1_handler(signum, frame):
     finally:
       self.host_proc.stdin.close()
 
-  def restore_default_browser(self):
-    # Restores the previous default browser settings in case the host crashes
-    # during a remote session. It's noop if the current default browser is not
-    # the CRD URL forwarder.
-
-    if not os.path.exists(SETUP_URL_FORWARDER_PATH):
-      print('Cannot find the URL forwarder setup script', file=sys.stderr)
-      return
-    print('Attempting to restore previous default browser...')
-    retcode = subprocess.call([SETUP_URL_FORWARDER_PATH, "--restore"],
-                              env=self.child_env)
-    if retcode != 0:
-      print('URL forwarder setup script returned a non-zero code:', retcode,
-            file=sys.stderr)
-
   def shutdown_all_procs(self):
     """Send SIGTERM to all procs and wait for them to exit. Will fallback to
     SIGKILL if a process doesn't exit within 10 seconds.
@@ -1301,7 +1284,6 @@ def cleanup():
 
   global g_desktop
   if g_desktop is not None:
-    g_desktop.restore_default_browser()
     g_desktop.shutdown_all_procs()
     if g_desktop.xorg_conf is not None:
       os.remove(g_desktop.xorg_conf)
@@ -1852,11 +1834,6 @@ def main():
       if desktop.host_proc is None:
         logging.info("Launching host process")
 
-        # Restore the previous default browser in case the daemon script has
-        # crashed or the system has been rebooted in the middle of a remote
-        # session.
-        desktop.restore_default_browser()
-
         extra_start_host_args = []
         if HOST_EXTRA_PARAMS_ENV_VAR in os.environ:
             extra_start_host_args = \

remoting/host/remote_open_url_message_handler.cc

@@ -8,7 +8,6 @@
 #include "base/callback_helpers.h"
 #include "base/logging.h"
 #include "remoting/base/compound_buffer.h"
-#include "remoting/host/scoped_url_forwarder.h"
 #include "remoting/protocol/message_serialization.h"
 #include "url/gurl.h"
 
@@ -51,7 +50,6 @@ RemoteOpenUrlMessageHandler::~RemoteOpenUrlMessageHandler() {
 void RemoteOpenUrlMessageHandler::OnConnected() {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 
-  scoped_url_forwarder_ = ScopedUrlForwarder::Create();
   ipc_server_.StartServer();
 }
 
@@ -80,7 +78,6 @@ void RemoteOpenUrlMessageHandler::OnIncomingMessage(
 void RemoteOpenUrlMessageHandler::OnDisconnecting() {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
 
-  scoped_url_forwarder_.reset();
   ipc_server_.StopServer();
 
   // The remote connection is going away, so inform all IPC clients to open the

remoting/host/remote_open_url_message_handler.h

@@ -19,8 +19,6 @@ class GURL;
 
 namespace remoting {
 
-class ScopedUrlForwarder;
-
 class RemoteOpenUrlMessageHandler final
     : public mojom::RemoteUrlOpener,
       public protocol::NamedMessagePipeHandler {
@@ -49,8 +47,6 @@ class RemoteOpenUrlMessageHandler final
   MojoIpcServer<mojom::RemoteUrlOpener> ipc_server_{
       GetRemoteOpenUrlIpcChannelName(), 0, this};
 
-  std::unique_ptr<ScopedUrlForwarder> scoped_url_forwarder_;
-
   static_assert(
       std::is_same<
           mojo::ReceiverId,

remoting/host/url_forwarder_configurator.cc

@@ -0,0 +1,27 @@
+// Copyright 2021 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 "remoting/host/url_forwarder_configurator.h"
+
+#include "base/macros.h"
+#include "build/build_config.h"
+
+namespace remoting {
+
+UrlForwarderConfigurator::UrlForwarderConfigurator() = default;
+
+UrlForwarderConfigurator::~UrlForwarderConfigurator() = default;
+
+#if !defined(OS_LINUX)
+
+// static
+UrlForwarderConfigurator* UrlForwarderConfigurator::GetInstance() {
+  // Unsupported platforms.
+  NOTREACHED();
+  return nullptr;
+}
+
+#endif  // !defined(OS_LINUX)
+
+}  // namespace remoting