Add options to GPU pixel test to use cloud storage for reference and error images.

tools/telemetry/telemetry/core/bitmap.py

 # Copyright 2013 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.
 import base64
 import cStringIO
 
 from telemetry.core import util
 
 util.AddDirToPythonPath(util.GetTelemetryDir(), 'third_party', 'png')
 import png  # pylint: disable=F0401
@@ skipping 74 matching lines @@
     """Returns a RgbaColor for the pixel at (x, y)."""
     base = self._bpp * (y * self._width + x)
     if self._bpp == 4:
       return RgbaColor(self._pixels[base + 0], self._pixels[base + 1],
                        self._pixels[base + 2], self._pixels[base + 3])
     return RgbaColor(self._pixels[base + 0], self._pixels[base + 1],
                      self._pixels[base + 2])
 
   def WritePngFile(self, path):
     with open(path, "wb") as f:
-      png.Writer(**self.metadata).write_array(f, self.pixels)
+      self.WritePngToFile(f)
+
+  def WritePngToFile(self, f):

[dtu, 2013/12/20 00:37:57]

WritePngToFileObject

Also unit test

[Ken Russell (switch to Gerrit), 2013/12/20 01:52:51]

Done.

+    png.Writer(**self._metadata).write_array(f, self.pixels)
 
   @staticmethod
   def FromPng(png_data):
     width, height, pixels, meta = png.Reader(bytes=png_data).read_flat()
     return Bitmap(4 if meta['alpha'] else 3, width, height, pixels, meta)
 
   @staticmethod
   def FromPngFile(path):
     with open(path, "rb") as f:
       return Bitmap.FromPng(f.read())
@@ skipping 108 matching lines @@
       self._metadata = meta
     finally:
       output.close()
 
     return self
 
   def ColorHistogram(self):
     """Returns a histogram of the pixel colors in this Bitmap."""
     # TODO(szym): Implement this.
     raise NotImplementedError("ColorHistogram not yet implemented.")