diff --git a/build.sh b/build.sh
deleted file mode 100755
index 9f319e9199..0000000000
--- a/build.sh
+++ /dev/null
@@ -1,52 +0,0 @@
-#!/bin/bash
-#
-# Copyright (c) 2013 Google Inc. All Rights Reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-#
-# ./build.sh {BuildType} {Module}
-#
-# The two parameters are optional, e.g.
-#
-# ./build.sh               # build all modules in Debug mode.
-# ./build.sh Release       # build all modules in Release mode.
-# ./build.sh Debug mp4     # build mp4 module in Debug mode.
-#
-# We use Ninja from Chrome to build our code. It's very very fast.
-#
-# A re-run of build.sh is required if there is any GYP file or build type
-# change. Otherwise, you may just run Ninja directly:
-#
-# ninja -C out/Debug   {Module}       # Again, Module is optional.
-# ninja -C out/Release {Module}       # Again, Module is optional.
-
-set -e
-
-function setup_packager_env() {
-  if [ $# -lt 1 ]; then
-    local type="Debug"
-  else
-    local type="$1"
-    if [[ "${type}" != "Release" &&
-          "${type}" != "Debug" ]]; then
-      echo "Incorrect BUILDTYPE ${type}"
-      return
-    fi
-  fi
-
-  # Note: You'd have to run ./tools/clang/scripts/update.sh before you run GYP
-  # with clang=1 flag.
-  export GYP_DEFINES="clang=1 use_openssl=1"
-  export BUILDTYPE="${type}"
-
-  export BUILD_OUT="."
-  export GYP_GENERATOR_FLAGS="output_dir=${BUILD_OUT}"
-  tools/gyp/gyp --depth=. --generator-output=out -I build/common.gypi --no-circular-check packager.gyp
-}
-
-export GYP_GENERATORS="ninja"
-setup_packager_env $@
-
-# Note: If this fails due to some error about "not having clang", read the note
-# above.
-ninja -C "out/${BUILDTYPE}" $2
diff --git a/gyp_packager.py b/gyp_packager.py
new file mode 100755
index 0000000000..734d2b4bb4
--- /dev/null
+++ b/gyp_packager.py
@@ -0,0 +1,76 @@
+#!/usr/bin/env python
+#
+# Copyright 2014 Google Inc. All rights reserved.
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+#
+# This script is a wrapper for Packager that adds some support for how GYP
+# is invoked by Packager.
+#
+# Build instructions:
+#
+# 1. Setup gyp: ./gyp_packager.py
+#
+# clang is not enabled by default, which can be enabled by overriding
+# GYP_DEFINE environment variable, i.e. "GYP_DEFINES='clang=1
+# use_openssl=1' ./gyp_packager.py".
+#
+# Ninja is the default build system. User can also change to make by
+# overriding GYP_GENERATORS to make, i.e. "GYP_GENERATORS='make'
+# ./gyp_packager.py".
+#
+# 2. The first step generates the make files but does not start the
+# build process. Ninja is the default build system. Refer to Ninja
+# manual on how to do the build.
+#
+# Common syntaxes: ninja -C out/{Debug/Release} [Module]
+# Module is optional. If not specified, build everything.
+#
+# Step 1 is only required if there is any gyp file change. Otherwise, you
+# may just run ninja.
+
+import os
+import sys
+
+src_dir = os.path.dirname(os.path.realpath(__file__))
+
+sys.path.insert(0, os.path.join(src_dir, 'tools', 'gyp', 'pylib'))
+import gyp
+
+if __name__ == '__main__':
+  args = sys.argv[1:]
+
+  # If we didn't get a gyp file, then fall back to assuming 'packager.gyp' from
+  # the same directory as the script.
+  if [arg.endswith('.gyp') for arg in args].count(True) == 0:
+    args.append(os.path.join(src_dir, 'packager.gyp'))
+
+  # Always include common.gypi.
+  args.extend(['-I' + os.path.join(src_dir, 'build/common.gypi')])
+
+  # Gyp should run from current directory.
+  args.append('--depth=.')
+
+  # Set GYP_DEFINES if it is not explicitly set yet.
+  if not os.environ.get('GYP_DEFINES'):
+    os.environ['GYP_DEFINES'] = 'use_openssl=1'
+
+  # There shouldn't be a circular dependency relationship between .gyp files,
+  # but in Chromium's .gyp files, on non-Mac platforms, circular relationships
+  # currently exist.  The check for circular dependencies is currently
+  # bypassed on other platforms, but is left enabled on the Mac, where a
+  # violation of the rule causes Xcode to misbehave badly.
+  if sys.platform not in ('darwin',):
+    args.append('--no-circular-check')
+
+  # Default to ninja, but only if no generator has explicitly been set.
+  if not os.environ.get('GYP_GENERATORS'):
+    os.environ['GYP_GENERATORS'] = 'ninja'
+
+  print 'Updating projects from gyp files...'
+  sys.stdout.flush()
+
+  # Off we go...
+  sys.exit(gyp.main(args))