[telemetry] Implement per-pixel algorithms in Bitmap as a C++ extension.

tools/telemetry/telemetry/core/bitmaptools/__init__.py

Index: tools/telemetry/telemetry/core/bitmaptools/__init__.py
diff --git a/tools/telemetry/telemetry/core/bitmaptools/__init__.py b/tools/telemetry/telemetry/core/bitmaptools/__init__.py
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index 0000000000000000000000000000000000000000..30a351f63881fece40a054a7c019b6b167866601
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+++ b/tools/telemetry/telemetry/core/bitmaptools/__init__.py
@@ -0,0 +1,72 @@
+# 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.
+
+""" Bitmap processing routines.
+
+All functions accept a tuple of (pixels, width, channels) as the first argument.
+Bounding box is a tuple (left, right, width, height).
+"""
+
+
+def _FixDistutilsMsvcCompiler():
+  # To avoid runtime mismatch, distutils should use the compiler which was used
+  # to build python. But our module does not use the runtime much, so it should
+  # be fine to build within a different environment.
+  # See also: http://bugs.python.org/issue7511
+  from distutils import msvc9compiler
+  for version in [msvc9compiler.get_build_version(), 9.0, 10.0, 11.0, 12.0]:
+    msvc9compiler.VERSION = version
+    try:
+      msvc9compiler.MSVCCompiler().initialize()
+      break
+    except Exception:
+      pass
+
+
+def _BuildExtension():
+  """Builds the extension library on demand."""
+  from distutils import log
+  from distutils.core import Distribution, Extension
+  import os
+  import tempfile
+
+  if os.name == 'nt':
+    _FixDistutilsMsvcCompiler()
+
+  build_dir = tempfile.mkdtemp()
+  dirname = os.path.dirname(__file__)
+  # Source file paths must be relative to current path.
+  relpath = os.path.relpath(dirname, os.getcwd())
+  src_files = [
+    os.path.join(relpath, 'bitmaptools.cc')
+  ]
+  dist = Distribution({
+    'ext_modules': [Extension('bitmaptools', src_files)]
+  })
+  dist.script_args = ['build_ext', '--build-temp', build_dir,
+                      '--build-lib', dirname]
+  dist.parse_command_line()
+  log.set_threshold(log.ERROR)
+  dist.run_commands()
+  dist.script_args = ['clean', '--build-temp', build_dir, '--all']
+  dist.parse_command_line()
+  log.set_threshold(log.ERROR)
+  dist.run_commands()
+
+
+try:
+  # Always re-build from source. No-op if source file older than the library.
+  _BuildExtension()
+except Exception:
+  # TODO(tonyg): fetch from cloudstorage
+  pass
+
+
+try:
+  # pylint: disable=W0401,F0401
+  from .bitmaptools import *
+except ImportError:
+  raise NotImplementedError(
+    'The bitmaptools module is not available for this platform.'
+  )