Merge ARM sysroot install script with existing x86/amd64 one.

DEPS

 # This file is used to manage the dependencies of the Chromium src repo. It is
 # used by gclient to determine what version of each dependency to check out, and
 # where.
 #
 # For more information, please refer to the official documentation:
 #   https://sites.google.com/a/chromium.org/dev/developers/how-tos/get-the-code
 #
 # When adding a new dependency, please update the top-level .gitignore file
 # to list the dependency's destination directory.
 #
@@ skipping 529 matching lines @@
     # Done in lieu of building the toolchain from scratch as it can take
     # anywhere from 30 minutes to 4 hours depending on platform to build.
     'name': 'nacltools',
     'pattern': '.',
     'action': [
         'python', 'src/build/download_nacl_toolchains.py',
         '--exclude', 'arm_trusted',
     ],
   },
   {
-    # Downloads an ARM sysroot image to src/arm-sysroot. This image updates
-    # at about the same rate that the chrome build deps change.
-    # This script is a no-op except for linux users who have
-    # target_arch=arm in their GYP_DEFINES.
-    'name': 'sysroot',
-    'pattern': '.',
-    'action': ['python', 'src/build/linux/install-arm-sysroot.py',
-               '--linux-only'],
-  },
-  {
     # Downloads the Debian Wheezy sysroot to chrome/installer/linux if needed.
     # This sysroot updates at about the same rate that the chrome build deps
     # change. This script is a no-op except for linux users who are doing
     # official chrome builds.
     'name': 'sysroot',
     'pattern': '.',
     'action': [
         'python',
         'src/chrome/installer/linux/sysroot_scripts/install-debian.wheezy.sysroot.py',
         '--linux-only',
         '--arch=amd64'],
   },
   {
     # Same as above, but for 32-bit Linux.
     'name': 'sysroot',
     'pattern': '.',
     'action': [
         'python',
         'src/chrome/installer/linux/sysroot_scripts/install-debian.wheezy.sysroot.py',
         '--linux-only',
         '--arch=i386'],
   },
   {
+    # Same as above, but for ARM Linux.
+    'name': 'sysroot',
+    'pattern': '.',
+    'action': [
+        'python',
+        'src/chrome/installer/linux/sysroot_scripts/install-debian.wheezy.sysroot.py',
+        '--linux-only',
+        '--arch=arm'],
+  },
+  {
     # Update the Windows toolchain if necessary.
     'name': 'win_toolchain',
     'pattern': '.',
     'action': ['python', 'src/build/vs_toolchain.py', 'update'],
   },
   {
     # Pull clang if needed or requested via GYP_DEFINES.
     # Note: On Win, this should run after win_toolchain, as it may use it.
     'name': 'clang',
     'pattern': '.',
@@ skipping 177 matching lines @@
     # corresponding .py files have already been deleted.
     'name': 'remove_stale_pyc_files',
     'pattern': 'src/tools/.*\\.py',
     'action': [
         'python',
         'src/tools/remove_stale_pyc_files.py',
         'src/tools',
     ],
   },
 ]