Add a script to manage the content shell command-line flags.

build/android/adb_content_shell_command_line

+#!/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.
+
+# If no flags are given, prints the current content shell flags.
+#
+# Otherwise, the given flags are used to REPLACE (not modify) the content shell
+# flags. For example:
+#   adb_content_shell_command_line --enable-webgl
+#
+# To remove all content shell flags, pass an empty string for the flags:
+#   adb_content_shell_command_line ""
+
+CMD_LINE_FILE=/data/local/tmp/content-shell-command-line
+
+if [ $# -eq 0 ] ; then
+  # If nothing specified, print the command line (stripping off "content_shell")
+  tempfile=$(tempfile)
+  adb pull $CMD_LINE_FILE $tempfile 2>/dev/null
+  if [ $? -eq 0 ] ; then
+    rm $tempfile
+    adb shell cat $CMD_LINE_FILE | cut -d " " -f "2-" 2>/dev/null
+  fi
+elif [ $# -eq 1 ] && [ "$1" = '' ] ; then
+  # If given an empty string, delete the command line.
+  set -x
+  adb shell rm $CMD_LINE_FILE >/dev/null
+else
+  # Else set it.
+  set -x
+  adb shell "echo 'content_shell $*' > $CMD_LINE_FILE"
+  # Prevent other apps from modifying flags -- this can create security issues.
+  adb shell chmod 0664 $CMD_LINE_FILE
+fi
+