Allow test and unittest_apk GN targets to use proguard

build/config/android/rules.gni

Index: build/config/android/rules.gni
diff --git a/build/config/android/rules.gni b/build/config/android/rules.gni
index f3076be1f42fe1222668cd1d6a9e9d011226a6cf..cdc898798b8906db0df0b9a0fec641ac591d7d69 100644
--- a/build/config/android/rules.gni
+++ b/build/config/android/rules.gni
@@ -2134,6 +2134,12 @@ template("unittest_apk") {
     # are defined, as otherwise test_suite_name would not be used.
     assert(test_suite_name != "")
 
+    if (defined(invoker.proguard_enabled) && invoker.proguard_enabled) {
+      assert(invoker.proguard_configs != [])
+      proguard_enabled = true
+      proguard_configs = invoker.proguard_configs
+    }
+
     if (!defined(apk_name)) {
       apk_name = test_suite_name
     }