When fetching try jobs for a CL, include only the latest for each builder.

third_party/WebKit/Tools/Scripts/webkitpy/common/net/rietveld.py

Index: third_party/WebKit/Tools/Scripts/webkitpy/common/net/rietveld.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/common/net/rietveld.py b/third_party/WebKit/Tools/Scripts/webkitpy/common/net/rietveld.py
index 5b9b1a8ae438d02886d09fb858b88ab52c20ccbc..9cb59ef3a19af5d497886dfa4ef5c536c7513675 100644
--- a/third_party/WebKit/Tools/Scripts/webkitpy/common/net/rietveld.py
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/common/net/rietveld.py
@@ -27,7 +27,8 @@ def latest_try_jobs(issue_number, builder_names, web, patchset_number=None):
         patchset_number: Use a specific patchset instead of the latest one.
 
     Returns:
-        A list of TryJob objects; empty list if none were found.
+        A list of TryJob objects for the latest job for each builder, on the
+        latest patchset. If none were found, an empty list is returned.
     """
     try:
         if patchset_number:
@@ -44,7 +45,7 @@ def latest_try_jobs(issue_number, builder_names, web, patchset_number=None):
         jobs.append(TryJob(
             builder_name=job['builder'],
             build_number=job['buildnumber']))
-    return jobs
+    return filter_latest_jobs(jobs)
 
 
 def _latest_patchset_url(issue_number, web):
@@ -80,6 +81,23 @@ def _patchset_url(issue_number, patchset_number):
     return '%s/%s' % (_issue_url(issue_number), patchset_number)
 
 
+def filter_latest_jobs(jobs):
+    """Filters out the list of jobs to include only the latest for each builder.
+
+    Args:
+        jobs: A list of TryJob objects.
+
+    Returns:
+        A list of TryJob objects such that only the latest job for each builder
+        is kept.
+    """
+    builder_to_highest_number = {}
+    for j in jobs:
+        if j.build_number > builder_to_highest_number.get(j.builder_name, 0):
+            builder_to_highest_number[j.builder_name] = j.build_number
+    return [j for j in jobs if builder_to_highest_number[j.builder_name] == j.build_number]
+
+
 def get_latest_try_job_results(issue_number, web):
     url = _latest_patchset_url(issue_number, web)
     patchset_data = _get_json(url, web)