Force gclient sync in safetynet_compare.py.

This overwrites deps that are dirty, fixing an issue with deps that are
removed in the "after" branch but not in the "before" branch.

Change-Id: I1c905dc46522455ad160a6fd57fbab979c42162e
Reviewed-on: https://pdfium-review.googlesource.com/42191
Reviewed-by: Ryan Harrison <rharrison@chromium.org>
Commit-Queue: Henrique Nakashima <hnakashima@chromium.org>
diff --git a/testing/tools/safetynet_compare.py b/testing/tools/safetynet_compare.py
index ef47eab..3c0de03 100755
--- a/testing/tools/safetynet_compare.py
+++ b/testing/tools/safetynet_compare.py
@@ -351,7 +351,8 @@
       cmd.append('--cache-dir=%s' % self.args.cache_dir)
     RunCommandPropagateErr(cmd, exit_status_on_error=1)
 
-    RunCommandPropagateErr(['gclient', 'sync'], exit_status_on_error=1)
+    RunCommandPropagateErr(['gclient', 'sync', '--force'],
+                           exit_status_on_error=1)
 
     PrintErr('Done.')
 
@@ -390,7 +391,8 @@
       build_dir: String with path to build directory
     """
     PrintErr('Syncing...')
-    RunCommandPropagateErr(['gclient', 'sync'], exit_status_on_error=1)
+    RunCommandPropagateErr(['gclient', 'sync', '--force'],
+                           exit_status_on_error=1)
     PrintErr('Done.')
 
     PrintErr('Building...')