[Telemetry] Migrate bitmap.py from bitmaptools.cc to numpy

content/test/gpu/gpu_tests/pixel.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.
 from datetime import datetime
 import glob
 import optparse
 import os
 import re
 
 import cloud_storage_test_base
@@ skipping 116 matching lines @@
     if not cur_revision:
       cur_revision = 0
 
     image_path = os.path.join(img_dir, img_name)
 
     self._DeleteOldReferenceImages(image_path, cur_revision)
 
     image_path = image_path + '_' + str(cur_revision) + '.png'
 
     try:
-      ref_png = bitmap.Bitmap.FromPngFile(image_path)
+      ref_png = bitmap.Bitmap.FromImageFile(image_path)
     except IOError:
       ref_png = None
 
     if ref_png:
       return ref_png
 
     print 'Reference image not found. Writing tab contents as reference.'
 
     self._WriteImage(image_path, screenshot)
     return screenshot
@@ skipping 10 matching lines @@
         default=default_reference_image_dir)
 
   def CreatePageSet(self, options):
     page_set = page_sets.PixelTestsPageSet()
     for page in page_set.pages:
       page.script_to_evaluate_on_commit = test_harness_script
     return page_set
 
   def CreateExpectations(self):
     return pixel_expectations.PixelExpectations()