[Cronet] add base proguard flags

components/cronet/android/BUILD.gn

 # Copyright 2015 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/buildflag_header.gni")
 import("//build/config/android/config.gni")
 import("//build/config/android/rules.gni")
 import("//build/util/version.gni")
 import("//chrome/version.gni")
 import("//testing/test.gni")
@@ skipping 383 matching lines @@
     "//base:base_java",
     "//third_party/jsr-305:jsr_305_javalib",
   ]
 
   run_findbugs_override = true
   if (!is_java_debug) {
     proguard_enabled = true
     proguard_configs = [
       "proguard.cfg",
       "sample/javatests/proguard.cfg",
+      "//base/android/base_proguard_config.flags",
     ]
   }
 }
 
 # cronet_sample_test_apk_resources is identical to
 # cronet_sample_apk_resources. The two have to be different targets because
 # targets which are common between the "instrumentation test apk" and the
 # "tested apk" are removed from the "instrumentation test apk".
 android_resources("cronet_sample_test_apk_resources") {
   resource_dirs = [ "sample/res" ]
@@ skipping 295 matching lines @@
     ":cronet_perf_test_apk_java",
     ":cronet_test_apk_java",
     "//base:base_java",
   ]
 
   run_findbugs_override = true
   proguard_enabled = true
   proguard_configs = [
     "proguard.cfg",
     "test/javaperftests/proguard.cfg",
+    "//base/android/base_proguard_config.flags",
   ]
 }
 
 test("cronet_unittests") {
   sources = [
     "//components/cronet/android/cert/cert_verifier_cache_serializer_unittest.cc",
     "//components/cronet/histogram_manager_unittest.cc",
     "//components/cronet/run_all_unittests.cc",
     "//components/cronet/url_request_context_config_unittest.cc",
   ]
@@ skipping 163 matching lines @@
     ":cronet_javadoc_classpath",
     ":jar_cronet_api_source",
   ]
 }
 
 copy("cronet_package_copy") {
   sources = [
     "$root_out_dir/lib.java/components/cronet/android/cronet_api.jar",
     "//AUTHORS",
     "//chrome/VERSION",
-    "//components/cronet/android/proguard.cfg",
   ]
   outputs = [
     "$_package_dir/{{source_file_part}}",
   ]
 
   deps = [
     ":cronet_api",
   ]
 }
 
+action("cronet_combine_proguard_flags") {
+  script = "//components/cronet/tools/generate_proguard_file.py"
+  outputs = [
+    "$_package_dir/proguard.cfg",
+  ]
+
+  args = [
+    "--output-file",
+    rebase_path("$_package_dir/proguard.cfg", root_build_dir),
+    rebase_path("//base/android/base_proguard_config.flags", root_build_dir),
+    rebase_path("//components/cronet/android/proguard.cfg", root_build_dir),
+  ]
+}
+
 copy("cronet_package_copy_native_lib") {
   sources = [
     "$root_out_dir/libcronet.so",
   ]
   outputs = [
     "$_package_dir/libs/${android_app_abi}/libcronet.so",
   ]
   deps = [
     ":cronet",
   ]
 }
 
 copy("cronet_package_copy_native_lib_unstripped") {
   sources = [
     "$root_out_dir/lib.unstripped/libcronet.so",
   ]
   outputs = [
     "$_package_dir/symbols/${android_app_abi}/libcronet.so",
   ]
   deps = [
     ":cronet",
   ]
 }
 
 group("cronet_package") {
   deps = [
+    ":cronet_combine_proguard_flags",
     ":cronet_package_copy",
     ":cronet_package_copy_native_lib",
     ":cronet_package_copy_native_lib_unstripped",
     ":generate_javadoc",
     ":generate_licenses",
     ":jar_cronet_api_source",
     ":jar_cronet_other_source",
     ":jar_cronet_sample_source",
     ":repackage_extracted_jars",
   ]
 }