toolchain-utils: add build link to daily trybot logs.

This adds build link to daily trybot logs. It also waits 2 hours
before polling the building status to trybot.

BUG=chromium:673419
TEST=The build link is added in the log.

Change-Id: I8fc0ea413ee0f40b398d6eb80c3308c5a1e7d793
Reviewed-on: https://chrome-internal-review.googlesource.com/311042
Commit-Ready: Yunlian Jiang <yunlian@google.com>
Tested-by: Yunlian Jiang <yunlian@google.com>
Reviewed-by: Caroline Tice <cmtice@google.com>
diff --git a/buildbot_test_toolchains.py b/buildbot_test_toolchains.py
index 91d4e3f..60bd69a 100755
--- a/buildbot_test_toolchains.py
+++ b/buildbot_test_toolchains.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python2
+#!/usr/bin/env python2
 """Script for running nightly compiler tests on ChromeOS.
 
 This script launches a buildbot to build ChromeOS with the latest compiler on
@@ -250,7 +250,7 @@
     date_str = datetime.date.today()
     description = 'master_%s_%s_%s' % (self._patches_string, self._build,
                                        date_str)
-    trybot_image = buildbot_utils.GetTrybotImage(
+    build_id, trybot_image = buildbot_utils.GetTrybotImage(
         self._chromeos_root,
         self._build,
         self._patches,
@@ -258,6 +258,9 @@
         other_flags=['--notests'],
         build_toolchain=True)
 
+    print('trybot_url: \
+       https://uberchromegw.corp.google.com/i/chromiumos.tryserver/builders/release/builds/%s' \
+       % build_id)
     if len(trybot_image) == 0:
       self._l.LogError('Unable to find trybot_image for %s!' % description)
       return 1