Do not obfuscate hamcrest classes

third_party/hamcrest/BUILD.gn

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/rules.gni")
 
 java_group("hamcrest_java") {
   testonly = true
   deps = [
     ":hamcrest_core_java",
     ":hamcrest_integration_java",
     ":hamcrest_library_java",
   ]
 }
 
 java_prebuilt("hamcrest_core_java") {
   supports_android = true
   testonly = true
   jar_path = "lib/hamcrest-core-1.3.jar"
+  proguard_configs = [ "//third_party/hamcrest/proguard.flags" ]
 }
 
 java_prebuilt("hamcrest_integration_java") {
   supports_android = true
   testonly = true
   jar_path = "lib/hamcrest-integration-1.3.jar"
+  proguard_configs = [ "//third_party/hamcrest/proguard.flags" ]
 }
 
 java_prebuilt("hamcrest_library_java") {
   supports_android = true
   testonly = true
   jar_path = "lib/hamcrest-library-1.3.jar"
+  proguard_configs = [ "//third_party/hamcrest/proguard.flags" ]
 }