[prpc] Add pRPC CLI tool to depot_tools.

This will be used when running infrastructure code locally
(e.g. recipes) to correctly interact with LUCI service APIs
(such as luci-scheduler.appspot.com).

It is also generically useful to explore and interact with LUCI
service APIs on the command line (for debugging/scripting).

R=tandrii@chromium.org, vadimsh@chromium.org

Bug: 808677
Change-Id: I41cfd4cc7e2d245d3a5d2be83f9879f92a8d1bca
Reviewed-on: https://chromium-review.googlesource.com/905457
Commit-Queue: Robbie Iannucci <iannucci@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Reviewed-by: Vadim Shtayura <vadimsh@chromium.org>

cipd_manifest.txt

@@ -15,3 +15,6 @@ infra/tools/luci/led/${platform}  git_revision:54b6b3102fbb15ca3e3bd762ff3df7b08
 
 # Mac toolchain installer
 infra/tools/mac_toolchain/${os=mac}-${arch} git_revision:d4dc0c29a004b59dcca1e69ae84eba0c932eb010
+
+# LUCI rpc command line tool
+infra/tools/prpc/${platform} git_revision:bf5820217a310115ae8b971dee6ff6cb894ea3bf

prpc

+#!/bin/bash
+
+# Copyright 2018 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.
+
+MYPATH=$(dirname "${BASH_SOURCE[0]}")
+
+source "$MYPATH/cipd_bin_setup.sh"
+cipd_bin_setup &> /dev/null
+
+exec "$MYPATH/.cipd_bin/prpc" "$@"
+

prpc.bat

+@echo off
+:: Copyright 2018 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.
+
+call "%~dp0\cipd_bin_setup.bat" > nul 2>&1
+"%~dp0\.cipd_bin\prpc.exe" %*
+