[test] Make perf runner able to pass extra flags to d8.

TEST=tools/run_perf.py --arch x64 --extra-flags="--turbo --turbo-verify-allocation --turbo-greedy-regalloc" /path/to/SunSpider.json
BUG=484208
LOG=n
TBR=tandrii@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/1128933007

Cr-Commit-Position: refs/heads/master@{#28384}

tools/run_perf.py

@@ -310,13 +310,14 @@ class Runnable(Graph):
     bench_dir = os.path.normpath(os.path.join(*self.path))
     os.chdir(os.path.join(suite_dir, bench_dir))
 
-  def GetCommandFlags(self):
+  def GetCommandFlags(self, extra_flags=None):
     suffix = ["--"] + self.test_flags if self.test_flags else []
-    return self.flags + [self.main] + suffix
+    return self.flags + (extra_flags or []) + [self.main] + suffix
 
-  def GetCommand(self, shell_dir):
+  def GetCommand(self, shell_dir, extra_flags=None):
     # TODO(machenbach): This requires +.exe if run on windows.
-    return [os.path.join(shell_dir, self.binary)] + self.GetCommandFlags()
+    cmd = [os.path.join(shell_dir, self.binary)]
+    return cmd + self.GetCommandFlags(extra_flags=extra_flags)
 
   def Run(self, runner):
     """Iterates over several runs and handles the output for all traces."""
@@ -474,6 +475,7 @@ class Platform(object):
 class DesktopPlatform(Platform):
   def __init__(self, options):
     self.shell_dir = options.shell_dir
+    self.extra_flags = options.extra_flags.split()
 
   def PreExecution(self):
     pass
@@ -487,8 +489,10 @@ class DesktopPlatform(Platform):
 
   def Run(self, runnable, count):
     try:
-      output = commands.Execute(runnable.GetCommand(self.shell_dir),
-                                timeout=runnable.timeout)
+      output = commands.Execute(
+          runnable.GetCommand(self.shell_dir, self.extra_flags),
+          timeout=runnable.timeout,
+      )
     except OSError as e:
       print ">>> OSError (#%d):" % (count + 1)
       print e
@@ -509,6 +513,7 @@ class AndroidPlatform(Platform):  # pragma: no cover
 
   def __init__(self, options):
     self.shell_dir = options.shell_dir
+    self.extra_flags = options.extra_flags.split()
     LoadAndroidBuildTools(options.android_build_tools)
 
     if not options.device:
@@ -596,7 +601,7 @@ class AndroidPlatform(Platform):  # pragma: no cover
     cache = cache_control.CacheControl(self.device)
     cache.DropRamCaches()
     binary_on_device = AndroidPlatform.DEVICE_DIR + runnable.binary
-    cmd = [binary_on_device] + runnable.GetCommandFlags()
+    cmd = [binary_on_device] + runnable.GetCommandFlags(self.extra_flags)
 
     # Relative path to benchmark directory.
     if runnable.path:
@@ -636,6 +641,9 @@ def Main(args):
   parser.add_option("--device",
                     help="The device ID to run Android tests on. If not given "
                          "it will be autodetected.")
+  parser.add_option("--extra-flags",
+                    help="Additional flags to pass to the test executable",
+                    default="")
   parser.add_option("--json-test-results",
                     help="Path to a file for storing json results.")
   parser.add_option("--outdir", help="Base directory with compile output",