Fix encoding problem with json validation in PRESUBMIT.py.

The presubmit script was calling out to a subprocess to discard
comments in json files.

https://codereview.chromium.org/1253453002
exposed some encoding issue when sending the Unicode content back
and forth.  Rather than trying to figure out how to get that right, just
import and use the json_comment_eater python module directly.

BUG=513181
TESTED=git cl presubmit passed for the above-mentioned CL .

Review URL: https://codereview.chromium.org/1248323002

Cr-Commit-Position: refs/heads/master@{#340071}
diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index c926dd7..a888b11 100644
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -1198,15 +1198,16 @@
   try:
     contents = input_api.ReadFile(filename)
     if eat_comments:
-      json_comment_eater = input_api.os_path.join(
-          input_api.PresubmitLocalPath(),
-          'tools', 'json_comment_eater', 'json_comment_eater.py')
-      process = input_api.subprocess.Popen(
-          [input_api.python_executable, json_comment_eater],
-          stdin=input_api.subprocess.PIPE,
-          stdout=input_api.subprocess.PIPE,
-          universal_newlines=True)
-      (contents, _) = process.communicate(input=contents)
+      import sys
+      original_sys_path = sys.path
+      try:
+        sys.path = sys.path + [input_api.os_path.join(
+            input_api.PresubmitLocalPath(),
+            'tools', 'json_comment_eater')]
+        import json_comment_eater
+      finally:
+        sys.path = original_sys_path
+      contents = json_comment_eater.Nom(contents)
 
     input_api.json.loads(contents)
   except ValueError as e: