Remove unnecessary include in gcp_strings.h

Remove the include of "base/values.h" since it doesn't need anything
from it.

Bug: 960460
Change-Id: I08050e552bd3d8ddad2b1e909a3e708168c488db
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1599511
Auto-Submit: Xiaohan Wang <xhwang@chromium.org>
Reviewed-by: Tien Mai <tienmai@chromium.org>
Commit-Queue: Xiaohan Wang <xhwang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#657362}

chrome/credential_provider/common/gcp_strings.h

@@ -8,8 +8,6 @@
 #include <string>
 #include <vector>
 
-#include "base/values.h"
-
 namespace credential_provider {
 
 // The the UI process can exit with the following exit code.