Build Clang using profile-guided optimization on Windows

This makes local Chromium builds 11% faster on Windows. Builds using
goma will not see the same speed-up, but it reduces the server load.

(This is already done on Linux and Mac since https://crrrev.com/671262)

Bug: 966403
Change-Id: I33c91893e2921f88922e2dae825da10f788d8774
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1807241Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Hans Wennborg <hans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#698887}

tools/clang/scripts/package.py

@@ -196,10 +196,7 @@ def main():
 
     build_cmd = [sys.executable, os.path.join(THIS_DIR, 'build.py'),
                  '--bootstrap', '--disable-asserts',
-                 '--run-tests']
-    if sys.platform != 'win32':
-      # TODO(hans): Use --pgo for the Windows package too.
-      build_cmd.append('--pgo')
+                 '--run-tests', '--pgo']
     if sys.platform.startswith('linux'):
       build_cmd.append('--lto-lld')
     TeeCmd(build_cmd, log)

tools/clang/scripts/update.py

@@ -39,7 +39,7 @@ import zipfile
 # Reverting problematic clang rolls is safe, though.
 CLANG_REVISION = '13bdae8541c3fc5acf6ee7de78ec5ab8446848e4'
 CLANG_SVN_REVISION = '372314'
-CLANG_SUB_REVISION = 1
+CLANG_SUB_REVISION = 2
 
 PACKAGE_VERSION = '%s-%s-%s' % (CLANG_SVN_REVISION, CLANG_REVISION[:8],
                                 CLANG_SUB_REVISION)