[blink] Allow blink files to include .mojom-blink-test-utils.h

This change adds .mojom-blink-test-utils.h to the list of allowed header
suffixes in the presubmit checks.

Bug: 922875
Change-Id: I2cb51817c43a56480ad780f40372dca67ae14e71
Reviewed-on: https://chromium-review.googlesource.com/c/1481088Reviewed-by: Kent Tamura <tkent@chromium.org>
Commit-Queue: Oksana Zhuravlova <oksamyt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#634546}

third_party/blink/PRESUBMIT.py

@@ -58,8 +58,8 @@ def _CheckForWrongMojomIncludes(input_api, output_api):
                     if f.LocalPath().startswith(public_folder) and \
                             not f.LocalPath() in allow_blink_files:
                         error_list = public_blink_mojom_errors
-                    elif match.group(1) not in ('-blink', '-blink-forward'):
-                        # Neither -shared.h, -blink.h nor -blink-forward.h.
+                    elif match.group(1) not in ('-blink', '-blink-forward', '-blink-test-utils'):
+                        # Neither -shared.h, -blink.h, -blink-forward.h nor -blink-test-utils.h.
                         error_list = non_blink_mojom_errors
 
             if error_list is not None:

third_party/blink/PRESUBMIT_test.py

@@ -129,6 +129,7 @@ class PresubmitTest(unittest.TestCase):
         potentially_bad_content = """
         #include "public/platform/modules/cache_storage.mojom-blink.h"
         #include "public/platform/modules/cache_storage.mojom-blink-forward.h"
+        #include "public/platform/modules/cache_storage.mojom-blink-test-utils.h"
         """
         mock_input_api.files = [
             MockAffectedFile('third_party/blink/renderer/core/a_header.h',