Add framework for basic cr command

go/src/infra/tools/cr/cmd/firstrun.go

+// Copyright 2016 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.
+
+/*
+Generally only executed once on a given machine, the firstrun command installs
+the cr tool, prepares a space for it to install modules, and adds it to $PATH.
+*/
+
+package cmd
+
+import (
+        "fmt"
+
+        "github.com/spf13/cobra"
+)
+
+var firstrunCmd = &cobra.Command{
+        Use:   "firstrun",
+        Short: "Install the cr tool and intelligently add it to $PATH",
+        Long: `Install the cr too and intelligently add it to $PATH.
+
+Given a path to a desired install directory, it takes ownership of that
+directory, sets it up to support installation of modules, and adds the
+directory to $PATH (by prompting to modify e.g. the registry or .bashrc).
+
+The firstrun command is intended to only be run once, when first
+installing the cr tool.`,
+        Run: func(cmd *cobra.Command, args []string) {
+                fmt.Println("firstrun called")
+        },
+}
+
+func init() {
+        RootCmd.AddCommand(firstrunCmd)
+}