adjust prefetch URL we hit in UploadRenderedSKPs, and display view URL in CompareRenderedSKPs

This goes along with https://codereview.chromium.org/453433004/
('rebaseline_server: allow live queries to examine JSONKEY_EXPECTEDRESULTS
or JSONKEY_ACTUALRESULTS')

For full context, see https://goto.google.com/CorrectnessTestingBigIssues

BUG=skia:1942
R=borenet@google.com

Author: epoger@google.com

Review URL: https://codereview.chromium.org/446373003
diff --git a/slave/skia_slave_scripts/compare_rendered_skps.py b/slave/skia_slave_scripts/compare_rendered_skps.py
index cf03e6f..b41dd54 100644
--- a/slave/skia_slave_scripts/compare_rendered_skps.py
+++ b/slave/skia_slave_scripts/compare_rendered_skps.py
@@ -9,12 +9,18 @@
 import sys
 
 from build_step import BuildStep
+import upload_rendered_skps
 
 
 class CompareRenderedSKPs(BuildStep):
 
   def _Run(self):
-    print 'TODO(epoger): Not yet implemented; see http://skbug.com/1942'
+    print ('To view the latest SKP renderings by this builder, see:\n%s' %
+           upload_rendered_skps.rebaseline_server_url(
+               directive='static/live-view.html#/live-view.html?',
+               builder_name=self._builder_name))
+    print ''
+    print 'TODO(epoger): Compare not yet implemented; see http://skbug.com/1942'
 
 
 if '__main__' == __name__:
diff --git a/slave/skia_slave_scripts/upload_rendered_skps.py b/slave/skia_slave_scripts/upload_rendered_skps.py
index 2558013..cbc7dc0 100644
--- a/slave/skia_slave_scripts/upload_rendered_skps.py
+++ b/slave/skia_slave_scripts/upload_rendered_skps.py
@@ -14,9 +14,10 @@
 from utils import gs_utils
 import skia_vars
 
-PREFETCH_URL_FORMATTER = (
-    'http://skia-tree-status.appspot.com/redirect/rebaseline-server/prefetch/'
-    'setADir={set_a_dir}&setBDir={set_b_dir}')
+URL_FORMATTER = (
+    'http://skia-tree-status.appspot.com/redirect/rebaseline-server/'
+    '{directive}setADir={actuals_summary_dir}&setBDir={actuals_summary_dir}&'
+    'setASection=expected-results&setBSection=actual-results')
 
 
 class UploadRenderedSKPs(BuildStep):
@@ -55,21 +56,18 @@
     # when any of the results changed.
     src_dir = os.path.abspath(self.playback_actual_summaries_dir)
     dest_bucket = self._gs_summaries_bucket
-    dest_dir = self._args['builder_name']
+    builder_name = self._builder_name
     if os.listdir(src_dir):
       print ('Uploading image summaries from %s to gs://%s/%s' % (
-          src_dir, dest_bucket, dest_dir))
+          src_dir, dest_bucket, builder_name))
       gs.upload_dir_contents(
-          source_dir=src_dir, dest_bucket=dest_bucket, dest_dir=dest_dir,
+          source_dir=src_dir, dest_bucket=dest_bucket, dest_dir=builder_name,
           upload_if=gs.UploadIf.IF_MODIFIED,
           predefined_acl=gs.PLAYBACK_CANNED_ACL,
           fine_grained_acl_list=gs.PLAYBACK_FINEGRAINED_ACL_LIST)
       # Tell rebaseline_server to prefetch latest SKP results.
-      prefetch_url = PREFETCH_URL_FORMATTER.format(
-          set_a_dir=urllib.quote('gs://%s/%s' % (dest_bucket, dest_dir),
-                                 safe=''),
-          set_b_dir=urllib.quote('repo:expectations/skp/%s' % dest_dir,
-                                 safe=''))
+      prefetch_url = rebaseline_server_url(
+          directive='prefetch/', builder_name=builder_name)
       print ('Triggering prefetch URL %s' % prefetch_url)
       with contextlib.closing(urllib.urlopen(prefetch_url)):
         pass
@@ -77,5 +75,21 @@
       print ('Skipping upload to Google Storage, because no image summaries '
              'in %s' % src_dir)
 
+
+def rebaseline_server_url(directive, builder_name):
+  """Returns the URL for results from this builder on rebaseline_server.
+
+  Args:
+    directive: part of the URL, indicating whether to generate a 'prefetch'
+        URL, a 'live-loader' URL, or a link to live-view.html
+    builder_name: name of this builder
+  """
+  bucket = skia_vars.GetGlobalVariable('skp_summaries_bucket')
+  return URL_FORMATTER.format(
+      directive=directive,
+      actuals_summary_dir=urllib.quote(
+          'gs://%s/%s' % (bucket, builder_name), safe=''))
+
+
 if '__main__' == __name__:
   sys.exit(BuildStep.RunBuildStep(UploadRenderedSKPs))