Improve cr_cronet.py - pass unknown options to test runner and debugger.

For example "cr_cronet.py test -f *Quic*" will run just Quic tests.

BUG=

Review URL: https://codereview.chromium.org/601863002

Cr-Commit-Position: refs/heads/master@{#297304}

components/cronet/tools/cr_cronet.py

@@ -28,8 +28,9 @@ def main():
   parser.add_argument('-r', '--release', action='store_true',
                       help='use release configuration')
 
-  options = parser.parse_args()
+  options, unknown_options = parser.parse_known_args()
   print options
+  print unknown_options
   gyp_defines = 'GYP_DEFINES="OS=android enable_websockets=0 '+ \
       'disable_file_support=1 disable_ftp_support=1 '+ \
       'use_icu_alternatives_on_android=1" '
@@ -52,7 +53,14 @@ def main():
     return run ('ninja -C ' + out_dir + ' cronet_sample_proguard_apk')
   if (options.command=='test'):
     return run ('build/android/test_runner.py instrumentation '+ \
-                release_arg + ' --test-apk=CronetTestInstrumentation')
+                release_arg + ' --test-apk=CronetTestInstrumentation ' + \
+                ' '.join(unknown_options))
+  if (options.command=='debug'):
+    return run ('build/android/adb_gdb --start ' + \
+                '--activity=.CronetTestActivity ' + \
+                '--program-name=CronetTest ' + \
+                '--package-name=org.chromium.cronet_test_apk ' + \
+                ' '.join(unknown_options))
 
   parser.print_help()
   return 1