Android: Fix fat lib toolchain in Trichrome.

Missed in https://crrev.com/c/1481019. Only causes errors when
resource whitelisting is enabled.

Tbr: agrieve@chromium.org
Bug: 935088
Change-Id: Ide099850512681bc6494995310e6c63ac7441365
Reviewed-on: https://chromium-review.googlesource.com/c/1485232Reviewed-by: Eric Stevenson <estevenson@chromium.org>
Commit-Queue: Eric Stevenson <estevenson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#634979}

chrome/android/BUILD.gn

@@ -1115,7 +1115,7 @@ if (current_toolchain == default_toolchain) {
 
       generate_resource_whitelist(_resource_whitelist_target) {
         _fat_lib_toolchain = ""
-        if (_is_monochrome) {
+        if (_is_monochrome || _is_trichrome) {
           # Always use the 32-bit library's whitelist since the 64-bit one is
           # webview-only.
           if (!android_64bit_target_cpu) {