[WebLayer] Allow needed material design resources in system webview

For the translate infobar WebLayer needs a couple Material Design
resources. Allow these as an exception to the exclusion of material
design resources in system_webview_apk_tmpl.gni, as without this
allowance TriChrome (and presumably standalone WebView)-powered WebLayer
crash when showing the translate infobar.

I didn't detect this when landing the initial CL enabling translate in
WebLayer because the default weblayer_shell build doesn't do this
exclusion.

Needed resources are the ones referenced here:

third_party/android_deps/libs/com_android_support_design/com_android_support_design.info:  "res/layout/design_layout_tab_icon.xml",
third_party/android_deps/libs/com_android_support_design/com_android_support_design.info:  "res/layout/design_layout_tab_text.xml",

Bug: 1025620
Change-Id: I63543aaa17b45829897cee999d372aecc156d750
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2250109Reviewed-by: Bo <boliu@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Colin Blundell <blundell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#779819}

android_webview/system_webview_apk_tmpl.gni

@@ -190,6 +190,12 @@ template("system_webview_apk_or_module_tmpl") {
       "${_material_package}/text_*",
     ]
 
+    if (webview_includes_weblayer) {
+      # These are used in WebLayer for the translate infobar
+      resource_exclusion_exceptions +=
+          [ "${_material_package}/design_layout_tab_*" ]
+    }
+
     # Copied from chrome_public_apk_tmpl.gni.
 
     # Remove unneeded entries from material design values.xml files.