Move logic of gyp_chromium into gyp_chromium.py

For historical reasons gyp_chromium.py was launcher script
for gyp_chromium and the python logic lived in the
gyp_chromium.  This change moves python code into the
.py file makes the extension-free gyp_chromium a launcher
for gyp_chromium.py.

Review URL: https://codereview.chromium.org/1216863010

Cr-Commit-Position: refs/heads/master@{#342887}


CrOS-Libchrome-Original-Commit: 1eeaa328a6e7d621857c0026d0a2dd448dbf0f65
diff --git a/build/gyp_chromium_test.py b/build/gyp_chromium_test.py
index 0c0e479..0ae74fa 100755
--- a/build/gyp_chromium_test.py
+++ b/build/gyp_chromium_test.py
@@ -14,9 +14,7 @@
 
 import mock
 
-# TODO(sbc): Make gyp_chromium more testable by putting the code in
-# a .py file.
-gyp_chromium = __import__('gyp_chromium')
+import gyp_chromium
 
 
 class TestGetOutputDirectory(unittest.TestCase):