webview: update downstream SDK support dep.

R has been upstreamed; change the WebView dependency to handle S instead
in preparation for future work.

Change-Id: I8105dfbf2b943302336e0ef79a2acc2321c3b127
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2329949
Commit-Queue: Richard Coles <torne@chromium.org>
Commit-Queue: Nate Fischer <ntfschr@chromium.org>
Auto-Submit: Richard Coles <torne@chromium.org>
Reviewed-by: Nate Fischer <ntfschr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#793362}

android_webview/BUILD.gn

@@ -361,9 +361,9 @@ java_group("android_webview_no_weblayer_java") {
     "//android_webview/support_library:support_lib_glue_java",
   ]
 
-  # If the R SDK isn't public yet, include the downstream code to support R.
-  if (!public_android_sdk && android_sdk_release == "r") {
-    deps += [ "//clank/android_webview/next:r_sdk_java" ]
+  # If the S SDK isn't public yet, include the downstream code to support S.
+  if (!public_android_sdk && android_sdk_release == "s") {
+    deps += [ "//clank/android_webview/next:s_sdk_java" ]
   }
 }