Pass error messages from native messaging to web-app.

remoting/host/setup/daemon_controller_delegate_linux.cc

Index: remoting/host/setup/daemon_controller_delegate_linux.cc
diff --git a/remoting/host/setup/daemon_controller_delegate_linux.cc b/remoting/host/setup/daemon_controller_delegate_linux.cc
index 4928b8614f43d630864af29a2cd1f64b1df656c6..c249adc27fd926a7e011df370fa688e729af0008 100644
--- a/remoting/host/setup/daemon_controller_delegate_linux.cc
+++ b/remoting/host/setup/daemon_controller_delegate_linux.cc
@@ -65,20 +65,25 @@ bool GetScriptPath(base::FilePath* result) {
 bool RunHostScriptWithTimeout(
     const std::vector<std::string>& args,
     base::TimeDelta timeout,
-    int* exit_code) {
-  DCHECK(exit_code);
+    const DaemonController::ErrorCallback& on_error) {
 
   // As long as we're relying on running an external binary from the
   // PATH, don't do it as root.
   if (getuid() == 0) {
-    LOG(ERROR) << "Refusing to run script as root.";
+    std::string error_message = "Refusing to run script as root";
+    LOG(ERROR) << error_message;
+    on_error.Run(error_message, FROM_HERE);
     return false;
   }
+
   base::FilePath script_path;
   if (!GetScriptPath(&script_path)) {
-    LOG(ERROR) << "GetScriptPath() failed.";
+    std::string error_message = "GetScriptPath() failed";
+    LOG(ERROR) << error_message;
+    on_error.Run(error_message, FROM_HERE);
     return false;
   }
+
   base::CommandLine command_line(script_path);
   for (unsigned int i = 0; i < args.size(); ++i) {
     command_line.AppendArg(args[i]);
@@ -98,24 +103,40 @@ bool RunHostScriptWithTimeout(
 
   base::Process process = base::LaunchProcess(command_line, options);
   if (!process.IsValid()) {
-    LOG(ERROR) << "Failed to run command: "
-               << command_line.GetCommandLineString();
+    std::string error_message =
+        "Failed to run command: " + command_line.GetCommandLineString();
+    LOG(ERROR) << error_message;
+    on_error.Run(error_message, FROM_HERE);
     return false;
   }
 
-  if (!process.WaitForExitWithTimeout(timeout, exit_code)) {
+  int exit_code;
+  if (!process.WaitForExitWithTimeout(timeout, &exit_code)) {
     process.Terminate(0, false);
-    LOG(ERROR) << "Timeout exceeded for command: "
-               << command_line.GetCommandLineString();
+    std::string error_message =
+        "Timeout exceeded for command: " + command_line.GetCommandLineString();
+    LOG(ERROR) << error_message;
+    on_error.Run(error_message, FROM_HERE);
     return false;
   }
 
+  if (exit_code != 0) {
+    std::ostringstream error_message;
+    error_message << "Non-zero exit code " << exit_code << " from command: "
+                  << command_line.GetCommandLineString();
+    LOG(ERROR) << error_message;
+    on_error.Run(error_message.str(), FROM_HERE);
+  }
+
   return true;
 }
 
-bool RunHostScript(const std::vector<std::string>& args, int* exit_code) {
+bool RunHostScript(const std::vector<std::string>& args,
+                   const DaemonController::ErrorCallback& on_error) {
   return RunHostScriptWithTimeout(
-      args, base::TimeDelta::FromMilliseconds(kDaemonTimeoutMs), exit_code);
+      args,
+      base::TimeDelta::FromMilliseconds(kDaemonTimeoutMs),
+      on_error);
 }
 
 }  // namespace
@@ -129,7 +150,7 @@ DaemonControllerDelegateLinux::~DaemonControllerDelegateLinux() {
 DaemonController::State DaemonControllerDelegateLinux::GetState() {
   base::FilePath script_path;
   if (!GetScriptPath(&script_path)) {
-    LOG(ERROR) << "GetScriptPath() failed.";
+    LOG(ERROR) << "GetScriptPath() failed";
     return DaemonController::STATE_UNKNOWN;
   }
   base::CommandLine command_line(script_path);
@@ -182,17 +203,14 @@ scoped_ptr<base::DictionaryValue> DaemonControllerDelegateLinux::GetConfig() {
 void DaemonControllerDelegateLinux::SetConfigAndStart(
     scoped_ptr<base::DictionaryValue> config,
     bool consent,
-    const DaemonController::CompletionCallback& done) {
+    const base::Closure& on_done,
+    const DaemonController::ErrorCallback& on_error) {
   // Add the user to chrome-remote-desktop group first.
   std::vector<std::string> args;
   args.push_back("--add-user");
-  int exit_code;
   if (!RunHostScriptWithTimeout(
           args, base::TimeDelta::FromSeconds(kSudoTimeoutSeconds),
-          &exit_code) ||
-      exit_code != 0) {
-    LOG(ERROR) << "Failed to add user to chrome-remote-desktop group.";
-    done.Run(DaemonController::RESULT_FAILED);
+          on_error)) {
     return;
   }
 
@@ -200,61 +218,67 @@ void DaemonControllerDelegateLinux::SetConfigAndStart(
   base::FilePath config_dir = GetConfigPath().DirName();
   if (!base::DirectoryExists(config_dir) &&
       !base::CreateDirectory(config_dir)) {
-    LOG(ERROR) << "Failed to create config directory " << config_dir.value();
-    done.Run(DaemonController::RESULT_FAILED);
+    std::string error_message =
+        "Failed to create config directory " + config_dir.value();
+    LOG(ERROR) << error_message;
+    on_error.Run(error_message, FROM_HERE);
     return;
   }
 
   // Write config.
   if (!HostConfigToJsonFile(*config, GetConfigPath())) {
-    LOG(ERROR) << "Failed to update config file.";
-    done.Run(DaemonController::RESULT_FAILED);
+    std::string error_message = "Failed to update config file";
+    LOG(ERROR) << error_message;
+    on_error.Run(error_message, FROM_HERE);
     return;
   }
 
   // Finally start the host.
   args.clear();
   args.push_back("--start");
-  DaemonController::AsyncResult result = DaemonController::RESULT_FAILED;
-  if (RunHostScript(args, &exit_code) && (exit_code == 0))
-    result = DaemonController::RESULT_OK;
-
-  done.Run(result);
+  if (RunHostScript(args, on_error)) {
+    on_done.Run();
+  }
 }
 
 void DaemonControllerDelegateLinux::UpdateConfig(
     scoped_ptr<base::DictionaryValue> config,
-    const DaemonController::CompletionCallback& done) {
+    const base::Closure& on_done,
+    const DaemonController::ErrorCallback& on_error) {
   scoped_ptr<base::DictionaryValue> new_config(
       HostConfigFromJsonFile(GetConfigPath()));
-  if (new_config)
-    new_config->MergeDictionary(config.get());
-  if (!new_config || !HostConfigToJsonFile(*new_config, GetConfigPath())) {
-    LOG(ERROR) << "Failed to update config file.";
-    done.Run(DaemonController::RESULT_FAILED);
+  if (!new_config) {
+    std::string error_message =
+        "Reading config from " + GetConfigPath().value() + " failed";
+    LOG(ERROR) << error_message;
+    on_error.Run(error_message, FROM_HERE);
+    return;
+  }
+
+  new_config->MergeDictionary(config.get());
+  if (!HostConfigToJsonFile(*new_config, GetConfigPath())) {
+    std::string error_message =
+        "Writing config to " + GetConfigPath().value() + " failed";
+    LOG(ERROR) << error_message;
+    on_error.Run(error_message, FROM_HERE);
     return;
   }
 
   std::vector<std::string> args;
   args.push_back("--reload");
-  int exit_code = 0;
-  DaemonController::AsyncResult result = DaemonController::RESULT_FAILED;
-  if (RunHostScript(args, &exit_code) && (exit_code == 0))
-    result = DaemonController::RESULT_OK;
-
-  done.Run(result);
+  if (RunHostScript(args, on_error)) {
+    on_done.Run();
+  }
 }
 
 void DaemonControllerDelegateLinux::Stop(
-    const DaemonController::CompletionCallback& done) {
+    const base::Closure& on_done,
+    const DaemonController::ErrorCallback& on_error) {
   std::vector<std::string> args;
   args.push_back("--stop");
-  int exit_code = 0;
-  DaemonController::AsyncResult result = DaemonController::RESULT_FAILED;
-  if (RunHostScript(args, &exit_code) && (exit_code == 0))
-    result = DaemonController::RESULT_OK;
-
-  done.Run(result);
+  if (RunHostScript(args, on_error)) {
+    on_done.Run();
+  }
 }
 
 DaemonController::UsageStatsConsent