Force HEAD revision on Clang and ASan Windows builders

masters/master.chromium.fyi/master.cfg

Index: masters/master.chromium.fyi/master.cfg
diff --git a/masters/master.chromium.fyi/master.cfg b/masters/master.chromium.fyi/master.cfg
index e9e6a47288726f5321c89b6a56e6e761aa9838f1..e9eb04b150952ddcd1384bff3e671f372b35ef83 100644
--- a/masters/master.chromium.fyi/master.cfg
+++ b/masters/master.chromium.fyi/master.cfg
@@ -885,6 +885,7 @@ f_chromium_win_clang = win_out().ChromiumFactory(
     factory_properties={
       'gclient_env': {
         'GYP_DEFINES': 'clang=1',
+        'LLVM_WIN_REVISION': 'HEAD',
     }})
 
 f_chromium_win_clang_dbg = win_out().ChromiumFactory(
@@ -895,6 +896,7 @@ f_chromium_win_clang_dbg = win_out().ChromiumFactory(
     factory_properties={
       'gclient_env': {
         'GYP_DEFINES': 'clang=1 component=static_library',
+        'LLVM_WIN_REVISION': 'HEAD',
     }})
 
 f_chromium_win_clang_asan = win_out().ChromiumFactory(
@@ -906,6 +908,7 @@ f_chromium_win_clang_asan = win_out().ChromiumFactory(
       'asan': True,
       'gclient_env': {
         'GYP_DEFINES': 'clang=1 asan=1 component=static_library disable_nacl=1',
+        'LLVM_WIN_REVISION': 'HEAD',
     }})
 
 f_chromium_win_ninja_shared_2013_dbg = win_out().ChromiumFactory(