Add rasterize_and_record_micro.fast_path_gpu_rasterization.key_silk_cases benchmark

tools/perf/benchmarks/repaint.py

Index: tools/perf/benchmarks/repaint.py
diff --git a/tools/perf/benchmarks/repaint.py b/tools/perf/benchmarks/repaint.py
index 353fbf997a5277ece076053cffee34fc24c9056b..0c8aefc69cd6ca84f54d9b5e3daf6da94a4de402 100644
--- a/tools/perf/benchmarks/repaint.py
+++ b/tools/perf/benchmarks/repaint.py
@@ -2,6 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+from benchmarks import silk_flags
 from measurements import repaint
 from telemetry import test
 
@@ -23,7 +24,4 @@ class RepaintGpuRasterizationKeyMobileSites(test.Test):
   test = repaint.Repaint
   page_set = 'page_sets/key_mobile_sites.py'
   def CustomizeBrowserOptions(self, options):
-    options.AppendExtraBrowserArgs('--enable-threaded-compositing')
-    options.AppendExtraBrowserArgs('--force-compositing-mode')
-    options.AppendExtraBrowserArgs('--enable-impl-side-painting')
-    options.AppendExtraBrowserArgs('--force-gpu-rasterization')
+    silk_flags.CustomizeBrowserOptionsForGpuRasterization(options)