sandwich: Implements network condition on WPR server and browser.

tools/android/loading/device_setup.py

Index: tools/android/loading/device_setup.py
diff --git a/tools/android/loading/device_setup.py b/tools/android/loading/device_setup.py
index 0fe95fd80d357944dd6ac6ae4c8c5b425a2080c0..0b48faf22e090b12b6949b0aa23cd464db540abd 100644
--- a/tools/android/loading/device_setup.py
+++ b/tools/android/loading/device_setup.py
@@ -105,12 +105,15 @@ def _SetUpDevice(device, package_info):
 
 @contextlib.contextmanager
 def WprHost(device, wpr_archive_path, record=False,
+            network_condition_name=None,
             disable_script_injection=False):
   """Launches web page replay host.
 
   Args:
     device: Android device.
     wpr_archive_path: host sided WPR archive's path.
+    network_condition_name: Network condition name available in
+        chrome_setup.NETWORK_CONDITIONS.
     record: Enables or disables WPR archive recording.
 
   Returns:
@@ -119,6 +122,11 @@ def WprHost(device, wpr_archive_path, record=False,
   """
   assert device
   if wpr_archive_path == None:
+    if record:
+      logging.error('WPR cannot record without a specified archive.')

[mattcary, 2016/02/19 15:40:17]

Do you want to assert rather than just logging an error? In many situations it's
better to not work at all rather than work incorrectly.

[gabadie, 2016/02/22 10:05:00]

Done.

+    if network_condition_name:
+      logging.error('WPR cannot emulate network condition without a specified' +
+                    'archive.')
     yield []
     return
 
@@ -129,6 +137,16 @@ def WprHost(device, wpr_archive_path, record=False,
       os.remove(wpr_archive_path)
   else:
     assert os.path.exists(wpr_archive_path)
+  if network_condition_name:
+    condition = chrome_setup.NETWORK_CONDITIONS[network_condition_name]
+    if record:
+      logging.warning('WPR network condition is ignored when recording.')
+    else:
+      wpr_server_args.extend([
+          '--down', chrome_setup.BandwidthToString(condition['download']),
+          '--up', chrome_setup.BandwidthToString(condition['upload']),
+          '--delay_ms', str(condition['latency']),
+          '--shaping_type', 'proxy'])
 
   if disable_script_injection:
     # Remove default WPR injected scripts like deterministic.js which