Create empty minimal payments targets

* This patch creates empty targets in the payments component which will
  contain the minimal dependencies needed by downstream GPay code.
* This allows downstream to depend on these targets before things are
  moved into it.

Bug: 1144488
Change-Id: Ib0d6a1e0ea9aae2988322e6632e890d5185e4b4a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2597559
Commit-Queue: Nick Burris <nburris@chromium.org>
Reviewed-by: Rouslan Solomakhin <rouslan@chromium.org>
Reviewed-by: Liquan (Max) Gu <maxlg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#838240}

components/payments/content/android/BUILD.gn

@@ -72,6 +72,10 @@ generate_jni("jni_headers") {
   ]
 }
 
+# Temporarily empty target for downstream to depend on before resources move.
+java_group("minimal_java_resources") {
+}
+
 android_resources("java_resources") {
   sources = payments_java_resources
   deps = [
@@ -185,6 +189,10 @@ android_library("java") {
   resources_package = "org.chromium.components.payments"
 }
 
+# Temporarily empty target for downstream to depend on before dependencies move.
+java_group("minimal_java") {
+}
+
 android_aidl("payment_details_update_service_aidl") {
   interface_file = "java/src/org/chromium/components/payments/payment_details_update_service.aidl"
   sources = [