chromium_3pp: Remove packager_vars.star and set package_prefix for trybot

With crrev.com/c/2637092, "package_paths" prop is removed so there is
no need to keep packager_vars.star.

Also set the package_prefix for trybot to "chromium_3pp".
Currently 3pp uploads package sources to CIPD, even with "force_build"
set to True (Behavior to-be-changed). With this package_prefix, sources
will be uploaded to CIPD path "experimental/chromium_3pp"

Bug: 1132368
Change-Id: I3b3e7cc36badda7687da967c2e4681bfcea6187f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2639229Reviewed-by: Garrett Beaty <gbeaty@chromium.org>
Commit-Queue: Haiyang Pan <hypan@google.com>
Cr-Commit-Position: refs/heads/master@{#845421}

infra/config/generated/cr-buildbucket.cfg

@@ -33,7 +33,7 @@ buckets {
         cipd_version: "refs/heads/master"
         cmd: "recipes"
       }
-      properties: "{\"$build/goma\":{\"use_luci_auth\":true},\"$kitchen\":{\"devshell\":true,\"git_auth\":true},\"$recipe_engine/isolated\":{\"server\":\"https://isolateserver.appspot.com\"},\"builder_group\":\"chromium.packager\",\"package_path\":[],\"platform\":\"linux-amd64\",\"recipe\":\"chromium_3pp\"}"
+      properties: "{\"$build/goma\":{\"use_luci_auth\":true},\"$kitchen\":{\"devshell\":true,\"git_auth\":true},\"$recipe_engine/isolated\":{\"server\":\"https://isolateserver.appspot.com\"},\"builder_group\":\"chromium.packager\",\"platform\":\"linux-amd64\",\"recipe\":\"chromium_3pp\"}"
       execution_timeout_secs: 10800
       build_numbers: YES
       service_account: "chromium-cipd-builder@chops-service-accounts.iam.gserviceaccount.com"
@@ -29228,7 +29228,7 @@ buckets {
         cipd_version: "refs/heads/master"
         cmd: "recipes"
       }
-      properties: "{\"$build/goma\":{\"use_luci_auth\":true},\"$kitchen\":{\"devshell\":true,\"git_auth\":true},\"$recipe_engine/isolated\":{\"server\":\"https://isolateserver.appspot.com\"},\"builder_group\":\"tryserver.chromium.packager\",\"package_path\":[],\"platform\":\"linux-amd64\",\"recipe\":\"chromium_3pp\"}"
+      properties: "{\"$build/goma\":{\"use_luci_auth\":true},\"$kitchen\":{\"devshell\":true,\"git_auth\":true},\"$recipe_engine/isolated\":{\"server\":\"https://isolateserver.appspot.com\"},\"builder_group\":\"tryserver.chromium.packager\",\"package_prefix\":\"chromium_3pp\",\"platform\":\"linux-amd64\",\"recipe\":\"chromium_3pp\"}"
       execution_timeout_secs: 14400
       expiration_secs: 7200
       caches {

infra/config/subprojects/chromium/ci.star

@@ -8,7 +8,6 @@ load("//lib/ci.star", "ci")
 load("//lib/consoles.star", "consoles")
 load("//console-header.star", "HEADER")
 load("//project.star", "settings")
-load("./packager_vars.star", "CHROMIUM_3PP_PROPERTIES")
 
 def main_console_if_on_branch():
     return branches.value(for_branches = "main")
@@ -1691,7 +1690,9 @@ ci.cipd_3pp_builder(
     ),
     schedule = "0 7 * * 0 *",
     triggered_by = [],
-    properties = CHROMIUM_3PP_PROPERTIES["3pp-linux-amd64-packager"],
+    properties = {
+        "platform": "linux-amd64",
+    },
 )
 
 ci.cipd_builder(

infra/config/subprojects/chromium/packager_vars.star

-# Copyright 2020 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-def _chromium_3pp_properties(*, package_paths, platform):
-    """Declares the properties of a builder that use the recipe chromium_3pp.
-
-    See https://chromium.googlesource.com/chromium/tools/build/+/master/recipes/recipes/chromium_3pp.proto
-    for the proto definitions.
-    """
-    return {
-        "package_path": package_paths,
-        "platform": platform,
-    }
-
-# Define the properties of chromium 3pp packagers and should be shared between
-# CI and matching try builders.
-CHROMIUM_3PP_PROPERTIES = {
-    "3pp-linux-amd64-packager": _chromium_3pp_properties(
-        platform = "linux-amd64",
-        package_paths = [],
-    ),
-}

infra/config/subprojects/chromium/try.star

@@ -7,7 +7,6 @@ load("//lib/builders.star", "cpu", "goma", "os", "xcode")
 load("//lib/consoles.star", "consoles")
 load("//lib/try.star", "try_")
 load("//project.star", "settings")
-load("./packager_vars.star", "CHROMIUM_3PP_PROPERTIES")
 
 try_.defaults.set(
     bucket = "try",
@@ -1587,7 +1586,10 @@ try_.chromium_win_builder(
 try_.cipd_3pp_builder(
     name = "3pp-linux-amd64-packager",
     os = os.LINUX_DEFAULT,
-    properties = CHROMIUM_3PP_PROPERTIES["3pp-linux-amd64-packager"],
+    properties = {
+        "platform": "linux-amd64",
+        "package_prefix": "chromium_3pp",
+    },
 )
 
 try_.gpu_chromium_android_builder(