Telemetry: extends Platform abstraction.

tools/telemetry/telemetry/core/chrome/platform.py

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 class Platform(object):
   """The platform that the target browser is running on.
 
-  Provides a limited interface to obtain stats from the platform itself, where
-  possible.
+  Provides a limited interface to interact with the platform itself, where
+  possible. It's important to note that platforms may not provide a specific
+  API, so check with IsFooBar() for availability.
   """
+  def __init__(self, platform_backend):

[achuithb, 2013/02/25 21:18:08]

This breaks PosssibleCrOSBrowser.Create at line 30:
https://code.google.com/codesearch#OAMlx_jo-ck/src/tools/telemetry/telemetry/...

+    self._platform_backend = platform_backend
 
-  def GetSurfaceCollector(self, trace_tag):
+  def IsRawDisplayFrameRateSupported(self):
     """Platforms may be able to collect GL surface stats."""
-    class StubSurfaceCollector(object):
-      def __init__(self, trace_tag):
-        pass
-      def __enter__(self):
-        pass
-      def __exit__(self, *args):
-        pass
+    return self._platform_backend.IsRawDisplayFrameRateSupported()
 
-    return StubSurfaceCollector(trace_tag)
+  def StartRawDisplayFrameRateMeasurement(self, trace_tag):
+    """Start measuring GL surface stats."""
+    return self._platform_backend.StartRawDisplayFrameRateMeasurement(trace_tag)
+
+  def StopRawDisplayFrameRateMeasurement(self):
+    """Stop measuring GL surface stats and print results."""
+    return self._platform_backend.StopRawDisplayFrameRateMeasurement()
+
+  def SetFullPerformanceModeEnabled(self, enabled):
+    """Platforms may tweak their CPU governor, system status, etc.
+
+    Most platforms can operate in a battery saving mode. While good for battery
+    life, this can cause confusing performance results and add noise. Turning
+    full performance mode on disables these features, which is useful for
+    performance testing.
+    """
+    return self._platform_backend.SetFullPerformanceModeEnabled(enabled)
+
+  def CanMonitorThermalThrottling(self):
+    """Platforms may be able to detect thermal throttling.
+
+    Some fan-less computers go into a reduced performance mode when their heat
+    exceeds a certain threshold. Performance tests in particular should use this
+    API to detect if this has happened and interpret results accordingly.
+    """
+    return self._platform_backend.CanMonitorThermalThrottling()
+
+  def IsThermallyThrottled(self):
+    """Returns True if the device is currently thermally throttled."""
+    return self._platform_backend.IsThermallyThrottled()
+
+  def HasBeenThermallyThrottled(self):
+    """Returns True if the device has been thermally throttled."""
+    return self._platform_backend.HasBeenThermallyThrottled()
+
+
+def EmptyPlatform():
+  class EmptyPlatformBackend(object):
+    def IsRawDisplayFrameRateSupported(self):
+      return False
+
+    def StartRawDisplayFrameRateMeasurement(self, _):
+      return NotImplementedError()
+
+    def StopRawDisplayFrameRateMeasurement(self):
+      return NotImplementedError()
+
+    def SetFullPerformanceModeEnabled(self, enabled):
+      pass
+
+    def CanMonitorThermalThrottling(self):
+      return False
+
+    def IsThermallyThrottled(self):
+      return NotImplementedError()
+
+    def HasBeenThermallyThrottled(self):
+      return NotImplementedError()
+
+  return Platform(EmptyPlatformBackend())