Move blink_perf.xml_http_request benchmark to tools/perf/contrib/ directory

tools/perf/core/benchmark_finders.py

 # Copyright 2015 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.
 import imp
 import inspect
 import os
 import sys
 
 from core import path_util
 from core import perf_benchmark
@@ skipping 26 matching lines @@
     for _, obj in inspect.getmembers(module):
       if (inspect.isclass(obj) and issubclass(obj, perf_benchmark.PerfBenchmark)
           and GetClassFilePath(obj) == benchmark_file_dir):
         benchmark_names.append(obj.Name())
     return sorted(benchmark_names)
   finally:
     sys.path = original_sys_path
 
 
 def GetAllPerfBenchmarks():
-  benchmarks_dir = path_util.GetPerfBenchmarksDir()
-  top_level_dir = os.path.join(benchmarks_dir, '..')
   return discover.DiscoverClasses(
-      benchmarks_dir, top_level_dir, benchmark_module.Benchmark,
+      start_dir=path_util.GetPerfBenchmarksDir(),
+      top_level_dir=path_util.GetPerfDir(),
+      base_class=benchmark_module.Benchmark,
       index_by_class_name=True).values()
+
+
+def GetAllContribBenchmarks():
+  return discover.DiscoverClasses(
+      start_dir=path_util.GetPerfContribDir(),
+      top_level_dir=path_util.GetPerfDir(),
+      base_class=benchmark_module.Benchmark,
+      index_by_class_name=True).values()