android envsetup.sh: Tweak comment at top of file.

Bug: 330631
Change-Id: I930ef6a08833811313cd4cec61a400d283d12aa6
Reviewed-on: https://chromium-review.googlesource.com/580128
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#488339}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 24dfd305c5d51a9ab7b8c52584a4b3097419d7d7

android/envsetup.sh

@@ -3,10 +3,10 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-# Sets up environment for building Chromium on Android.
+# Adds Android SDK tools and related helpers to PATH, useful for development.
+# Not used on bots. Use like `. build/android/envsetup.sh`.
 
-# Make sure we're being sourced (possibly by another script). Check for bash
-# since zsh sets $0 when sourcing.
+# Make sure we're being sourced.
 if [[ -n "$BASH_VERSION" && "${BASH_SOURCE:-$0}" == "$0" ]]; then
   echo "ERROR: envsetup must be sourced."
   exit 1
@@ -19,11 +19,8 @@ android_envsetup_main() {
   local CHROME_SRC="$(readlink -f "${SCRIPT_DIR}/../../")"
   local ANDROID_SDK_ROOT="${CHROME_SRC}/third_party/android_tools/sdk/"
 
-  # Add Android SDK and utility tools to the system path.
   export PATH=$PATH:${ANDROID_SDK_ROOT}/platform-tools
   export PATH=$PATH:${ANDROID_SDK_ROOT}/tools/
-
-  # Add Chromium Android development scripts to the system path.
   export PATH=$PATH:${CHROME_SRC}/build/android
 }
 # In zsh, $0 is the name of the file being sourced.