Defer running of install_commands.Installed() until necessary

build/android/pylib/device/device_utils.py

Index: build/android/pylib/device/device_utils.py
diff --git a/build/android/pylib/device/device_utils.py b/build/android/pylib/device/device_utils.py
index 3ee69401378df6f66cb541e0e6b752dca424671a..1faa98e81b4e527659744834c235af704e7a8523 100644
--- a/build/android/pylib/device/device_utils.py
+++ b/build/android/pylib/device/device_utils.py
@@ -1145,12 +1145,10 @@ class DeviceUtils(object):
         len(host_device_tuples), dir_file_count, dir_size, False)
     zip_duration = self._ApproximateDuration(1, 1, size, True)
 
-    self._InstallCommands()
-
     if dir_push_duration < push_duration and (
-        dir_push_duration < zip_duration or not self._commands_installed):
+        dir_push_duration < zip_duration or not self._MaybeInstallCommands()):
       self._PushChangedFilesIndividually(host_device_tuples)
-    elif push_duration < zip_duration or not self._commands_installed:
+    elif push_duration < zip_duration or not self._MaybeInstallCommands():
       self._PushChangedFilesIndividually(files)
     else:
       self._PushChangedFilesZipped(files)
@@ -1158,7 +1156,7 @@ class DeviceUtils(object):
           ['chmod', '-R', '777'] + [d for _, d in host_device_tuples],
           as_root=True, check_return=True)
 
-  def _InstallCommands(self):
+  def _MaybeInstallCommands(self):
     if self._commands_installed is None:
       try:
         if not install_commands.Installed(self):
@@ -1167,6 +1165,7 @@ class DeviceUtils(object):
       except Exception as e:
         logging.warning('unzip not available: %s' % str(e))
         self._commands_installed = False
+    return self._commands_installed
 
   @staticmethod
   def _ApproximateDuration(adb_calls, file_count, byte_count, is_zipping):