Point to script that automates more of the roll

Change-Id: Id2f645e869506c8a5870131cdb3b9921e37bace2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2238889Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Arthur Eubanks <aeubanks@google.com>
Cr-Commit-Position: refs/heads/master@{#776806}

docs/updating_clang.md

@@ -9,48 +9,19 @@ An archive of all packages built so far is at https://is.gd/chromeclang
 1.  Check that https://ci.chromium.org/p/chromium/g/chromium.clang/console
     looks reasonably green.
 1.  Sync your Chromium tree to the latest revision to pick up any plugin
-    changes
-1.  Run `python tools/clang/scripts/upload_revision.py NNNN`
-    with the target LLVM SVN revision number. This creates a roll CL on a new
-    branch, uploads it and starts tryjobs that run upstream tests and build
-    the compiler binaries into a staging bucket on Google Cloud Storage (GCS).
-1.  If the clang upload try bots succeed, copy the binaries from the staging
-    bucket to the production one. For example:
-
-    ```shell
-    $ export rev=n123456-abcd1234-1
-    $ for x in Linux_x64 Mac Win ; do \
-        gsutil.py cp -n -a public-read gs://chromium-browser-clang-staging/$x/clang-$rev.tgz \
-            gs://chromium-browser-clang/$x/clang-$rev.tgz ; \
-        gsutil.py cp -n -a public-read gs://chromium-browser-clang-staging/$x/clang-$rev-buildlog.txt \
-            gs://chromium-browser-clang/$x/clang-$rev-buildlog.txt ; \
-        gsutil.py cp -n -a public-read gs://chromium-browser-clang-staging/$x/clang-tidy-$rev.tgz \
-            gs://chromium-browser-clang/$x/clang-tidy-$rev.tgz ; \
-        gsutil.py cp -n -a public-read gs://chromium-browser-clang-staging/$x/llvmobjdump-$rev.tgz \
-            gs://chromium-browser-clang/$x/llvmobjdump-$rev.tgz ; \
-        gsutil.py cp -n -a public-read gs://chromium-browser-clang-staging/$x/translation_unit-$rev.tgz \
-            gs://chromium-browser-clang/$x/translation_unit-$rev.tgz ; \
-        gsutil.py cp -n -a public-read gs://chromium-browser-clang-staging/$x/llvm-code-coverage-$rev.tgz \
-            gs://chromium-browser-clang/$x/llvm-code-coverage-$rev.tgz ; \
-        gsutil.py cp -n -a public-read gs://chromium-browser-clang-staging/$x/libclang-$rev.tgz \
-            gs://chromium-browser-clang/$x/libclang-$rev.tgz ; \
-        done && gsutil.py cp -n -a public-read gs://chromium-browser-clang-staging/Mac/lld-$rev.tgz \
-            gs://chromium-browser-clang/Mac/lld-$rev.tgz
-    ```
-
-    **Note** that writing to this bucket requires special permissions. File a
-    bug at g.co/bugatrooper if you don't have these already (e.g.,
-    https://crbug.com/1034081).
-
-1.  Run the goma package update script to push these packages to goma. If you do
-    not have the necessary credentials to do the upload, ask clang@chromium.org
-    to find someone who does
+    changes.
+1.  Run go/chrome-push-clang-to-goma. This takes a recent dry run CL to update
+    clang, and if the trybots were successful it will copy the binaries from
+    the staging bucket to the production one. Writing to this bucket requires
+    special permissions. File a bug at g.co/bugatrooper if you don't have these
+    already (e.g., https://crbug.com/1034081). Then it will push the packages
+    to goma. If you do not have the necessary credentials to do the upload, ask
+    clang@chromium.org to find someone who does.
 1.  Run an exhaustive set of try jobs to test the new compiler. The CL
-    description created by upload_revision.py includes `Cq-Include-Trybots:`
-    lines for all needed bots, so it's sufficient to just run `git cl try`
-    (or hit "CQ DRY RUN" on gerrit).
-
-1.  Commit roll CL from the first step
+    description created previously by upload_revision.py includes
+    `Cq-Include-Trybots:` lines for all needed bots, so it's sufficient to just
+    run `git cl try` (or hit "CQ DRY RUN" on gerrit).
+1.  Commit the roll CL from the previous step.
 1.  The bots will now pull the prebuilt binary, and goma will have a matching
     binary, too.