android envsetup: Stop exporting ANDROID_SDK_ROOT.

build/android/envsetup.sh

 #!/bin/bash
 # Copyright (c) 2012 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.
 
 # Sets up environment for building Chromium on Android.
 
 # Make sure we're being sourced (possibly by another script). Check for bash
 # since zsh sets $0 when sourcing.
 if [[ -n "$BASH_VERSION" && "${BASH_SOURCE:-$0}" == "$0" ]]; then
@@ skipping 18 matching lines @@
     # Otherwise, it will equal to "${CURRENT_DIR}"
     echo "Warning: Current directory is out of CHROME_SRC, it may not be \
   the one you want."
     echo "${CHROME_SRC}"
   fi
 
   # Allow the caller to override a few environment variables. If any of them is
   # unset, we default to a sane value that's known to work. This allows for
   # experimentation with a custom SDK.
   if [[ -z "${ANDROID_SDK_ROOT}" || ! -d "${ANDROID_SDK_ROOT}" ]]; then
-    export ANDROID_SDK_ROOT="${CHROME_SRC}/third_party/android_tools/sdk/"
+    local ANDROID_SDK_ROOT="${CHROME_SRC}/third_party/android_tools/sdk/"
   fi
 
   # Add Android SDK tools to system path.
   export PATH=$PATH:${ANDROID_SDK_ROOT}/tools
   export PATH=$PATH:${ANDROID_SDK_ROOT}/platform-tools
 
   # Add Chromium Android development scripts to system path.
   # Must be after CHROME_SRC is set.
   export PATH=$PATH:${CHROME_SRC}/build/android
 }
 android_envsetup_main
 
 android_gyp() {
   echo "Please call build/gyp_chromium instead. android_gyp is going away."
   "${CHROME_SRC}/build/gyp_chromium" --depth="${CHROME_SRC}" --check "$@"
 }