add tools/dm_flags.py

BUG=skia:

Review URL: https://codereview.chromium.org/950903003
diff --git a/tools/dm_flags.py b/tools/dm_flags.py
new file mode 100755
index 0000000..3b794ff
--- /dev/null
+++ b/tools/dm_flags.py
@@ -0,0 +1,122 @@
+#!/usr/bin/env python
+
+usage = '''
+Write extra flags to outfile for DM based on the bot name:
+  $ python dm_flags.py outfile Test-Mac10.9-MacMini6.2-HD4000-x86_64-Release
+Or run self-tests:
+  $ python dm_flags.py test
+'''
+
+import inspect
+import json
+import os
+import sys
+
+
+def lineno():
+  caller = inspect.stack()[1]  # Up one level to our caller.
+  return inspect.getframeinfo(caller[0]).lineno
+
+
+cov_start = lineno()+1   # We care about coverage starting just past this def.
+def get_dm_args(bot):
+  args = []
+
+  configs = ['565', '8888', 'gpu', 'nvprmsaa']
+  # Xoom and NP are running out of RAM when we run all these modes.  skia:3255
+  if ('Xoom'        not in bot and
+      'NexusPlayer' not in bot):
+    configs.extend(mode + '-8888' for mode in
+                   ['serialize', 'tiles_rt', 'pipe'])
+    configs.append('tiles_rt-gpu')
+  if 'ANGLE' in bot:
+    configs.append('angle')
+  args.append('--config')
+  args.extend(configs)
+
+  blacklist = []
+  # This image is too large to be a texture for many GPUs.
+  blacklist.extend('gpu _ PANO_20121023_214540.jpg'.split(' '))
+  blacklist.extend('msaa _ PANO_20121023_214540.jpg'.split(' '))
+
+  # Drawing SKPs or images into GPU canvases is a New Thing.
+  # It seems like we're running out of RAM on some Android bots, so start off
+  # with a very wide blacklist disabling all these tests on all Android bots.
+  if 'Android' in bot:  # skia:3255
+    blacklist.extend('gpu skp _ gpu image _ gpu subset _'.split(' '))
+    blacklist.extend('msaa skp _ msaa image _ gpu subset _'.split(' '))
+
+  if blacklist:
+    args.append('--blacklist')
+    args.extend(blacklist)
+
+  match = []
+  if 'Alex' in bot:  # skia:2793
+    # This machine looks to be running out of heap.
+    # Running with fewer threads may help.
+    args.extend(['--threads', '1'])
+  if 'Valgrind' in bot: # skia:3021
+    match.append('~Threaded')
+  if 'Xoom' in bot:  # skia:1699
+    match.append('~WritePixels')
+
+  # skia:3249: these images flakily don't decode on Android.
+  if 'Android' in bot:
+    match.append('~tabl_mozilla_0')
+    match.append('~desk_yahoonews_0')
+
+  if match:
+    args.append('--match')
+    args.extend(match)
+
+  # Though their GPUs are interesting, these don't test anything on
+  # the CPU that other ARMv7+NEON bots don't test faster (N5).
+  if ('Nexus10'  in bot or
+      'Nexus7'   in bot or
+      'GalaxyS3' in bot or
+      'GalaxyS4' in bot):
+    args.append('--nocpu')
+  return args
+cov_end = lineno()   # Don't care about code coverage past here.
+
+
+def self_test():
+  import coverage  # This way the bots don't need coverage.py to be installed.
+  args = {}
+  cases = [
+    'Test-Android-Nexus7-Tegra3-Arm7-Release',
+    'Test-Android-Xoom-Tegra2-Arm7-Release',
+    'Test-ChromeOS-Alex-GMA3150-x86-Debug',
+    'Test-Ubuntu12-ShuttleA-GTX550Ti-x86_64-Release-Valgrind',
+    'Test-Win7-ShuttleA-HD2000-x86-Debug-ANGLE',
+  ]
+
+  cov = coverage.coverage()
+  cov.start()
+  for case in cases:
+    args[case] = get_dm_args(case)
+  cov.stop()
+
+  this_file = os.path.basename(__file__)
+  _, _, not_run, _ = cov.analysis(this_file)
+  filtered = [line for line in not_run if line > cov_start and line < cov_end]
+  if filtered:
+    print 'Lines not covered by test cases: ', filtered
+    sys.exit(1)
+
+  golden = this_file.replace('.py', '.json')
+  with open(os.path.join(os.path.dirname(__file__), golden), 'w') as f:
+    json.dump(args, f, indent=2, sort_keys=True)
+
+
+if __name__ == '__main__':
+  if len(sys.argv) == 2 and sys.argv[1] == 'test':
+    self_test()
+    sys.exit(0)
+
+  if len(sys.argv) != 3:
+    print usage
+    sys.exit(1)
+
+  with open(sys.argv[1], 'w') as out:
+    json.dump(get_dm_args(sys.argv[2]), out)