[Telemetry] Add MeasureMemory method to action_runner

telemetry/telemetry/internal/actions/action_runner.py

Index: telemetry/telemetry/internal/actions/action_runner.py
diff --git a/telemetry/telemetry/internal/actions/action_runner.py b/telemetry/telemetry/internal/actions/action_runner.py
index 19dc78ec1782fc15c6f2a0e5d9c124e66b983a61..f51f6a3ff1562d092095a29f82ad9eeef9ddf0ac 100644
--- a/telemetry/telemetry/internal/actions/action_runner.py
+++ b/telemetry/telemetry/internal/actions/action_runner.py
@@ -28,6 +28,9 @@ from telemetry.internal.actions.wait import WaitForElementAction
 from telemetry.web_perf import timeline_interaction_record
 
 
+_DUMP_WAIT_TIME = 3
+
+
 class ActionRunner(object):
 
   def __init__(self, tab, skip_waits=False):
@@ -104,6 +107,30 @@ class ActionRunner(object):
     """
     return self.CreateInteraction('Gesture_' + label, repeatable)
 
+  def MeasureMemory(self, deterministic_mode=False):
+    """Add a memory measurement to the trace being recorded.
+
+    Behaves as a no-op if tracing is not enabled.
+
+    TODO(perezju): Also behave as a no-op if tracing is enabled but
+    memory-infra is not.
+
+    Args:
+      deterministic_mode: A boolean indicating whether to attempt or not to
+          control the environment (force GCs, clear caches) before making the
+          measurement in an attempt to obtain more deterministic results.
+    """
+    platform = self.tab.browser.platform
+    if not platform.tracing_controller.is_tracing_running:
+      logging.warning('Tracing is off. No memory dumps are being recorded.')
+      return
+    if deterministic_mode:
+      self.Wait(_DUMP_WAIT_TIME)
+      self.ForceGarbageCollection()
+      platform.FlushEntireSystemCache()
+      self.Wait(_DUMP_WAIT_TIME)
+    assert self.tab.browser.DumpMemory(), 'Unable to obtain memory dump'
+
   def Navigate(self, url, script_to_evaluate_on_commit=None,
                timeout_in_seconds=60):
     """Navigates to |url|.