Download sysroot from "commondatastorage.googleapis.com"

build/linux/sysroot_scripts/install-sysroot.py

Index: build/linux/sysroot_scripts/install-sysroot.py
diff --git a/build/linux/sysroot_scripts/install-sysroot.py b/build/linux/sysroot_scripts/install-sysroot.py
index b8f34edb3ff822bc2474908d40b8e4a18ee79224..591999d566accb6d12b3a8aea162b77d23ed27c5 100755
--- a/build/linux/sysroot_scripts/install-sysroot.py
+++ b/build/linux/sysroot_scripts/install-sysroot.py
@@ -91,11 +91,6 @@ def DetectTargetArch():
 
   This works by looking for target_arch in GYP_DEFINES.
   """
-  # TODO(agrieve): Make this script not depend on GYP_DEFINES so that it works
-  #     with GN as well.
-  gyp_environment.SetEnvironment()
-  supplemental_includes = gyp_chromium.GetSupplementalFiles()
-  gyp_defines = gyp_chromium.GetGypVars(supplemental_includes)
   target_arch = gyp_defines.get('target_arch')
   if target_arch == 'x64':
     return 'amd64'
@@ -139,6 +134,10 @@ def main():
   if options.running_as_hook and not sys.platform.startswith('linux'):
     return 0
 
+  if gyp_defines.has_key('use_sysroot') \
+      and int(gyp_defines['use_sysroot']) == 0:

[Sam Clegg, 2015/12/17 22:17:06]

What about just `gyp_defines.get('use_sysroot') == '0':`

+    return 0
+
   if options.running_as_hook:
     InstallDefaultSysroots()
   else:
@@ -216,4 +215,11 @@ if __name__ == '__main__':
   parser.add_option('--arch', type='choice', choices=valid_archs,
                     help='Sysroot architecture: %s' % ', '.join(valid_archs))
   options, _ = parser.parse_args()
+
+  # TODO(agrieve): Make this script not depend on GYP_DEFINES so that it works
+  #     with GN as well.
+  gyp_environment.SetEnvironment()
+  supplemental_includes = gyp_chromium.GetSupplementalFiles()
+  gyp_defines = gyp_chromium.GetGypVars(supplemental_includes)

[Sam Clegg, 2015/12/17 22:15:45]

Can you do this in main and pass gyp_defines to DetectTargetArch().

+
   sys.exit(main())