Android: Hook up aapt's main dex proguard rules

build/config/android/rules.gni

 # Copyright 2014 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.
 
 # Do not add any imports to non-//build directories here.
 # Some projects (e.g. V8) do not have non-build directories DEPS'ed in.
 import("//build/config/android/config.gni")
 import("//build/config/android/internal_rules.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/dcheck_always_on.gni")
@@ skipping 1653 matching lines @@
         shared_libraries_runtime_deps_file = _runtime_deps_file
       }
       if (_secondary_abi_native_libs_deps != []) {
         secondary_abi_shared_libraries_runtime_deps_file =
             _secondary_abi_runtime_deps_file
       }
     }
 
     _final_deps = []
 
+    if (enable_multidex) {
+      _generated_proguard_main_dex_config =
+          "$base_path.resources.main-dex-proguard.txt"
+    }
     _generated_proguard_config = "$base_path.resources.proguard.txt"
     process_resources_target = "${_template_name}__process_resources"
     process_resources(process_resources_target) {
       forward_variables_from(invoker,
                              [
                                "alternative_android_sdk_jar",
                                "android_aapt_path",
                                "app_as_shared_lib",
                                "include_all_resources",
                                "shared_resources",
                              ])
       srcjar_path = "${target_gen_dir}/${target_name}.srcjar"
       r_text_out_path = "${target_gen_dir}/${target_name}_R.txt"
       android_manifest = _android_manifest
       resource_dirs = [ "//build/android/ant/empty/res" ]
       zip_path = resources_zip_path
       all_resources_zip_path = _all_resources_zip_path
       generate_constant_ids = true
       proguard_file = _generated_proguard_config
+      if (enable_multidex) {
+        proguard_file_main_dex = _generated_proguard_main_dex_config
+      }
 
       build_config = _build_config
       deps = _android_manifest_deps + [ ":$build_config_target" ]
       if (defined(invoker.deps)) {
         deps += invoker.deps
       }
     }
     _srcjar_deps += [ ":$process_resources_target" ]
 
     if (_native_libs_deps != []) {
@@ skipping 226 matching lines @@
       inputs = [
         _build_config,
       ]
       sources = _dex_sources
       output = final_dex_path
 
       # All deps are already included in _dex_sources when proguard is used.
       if (!_proguard_enabled) {
         if (enable_multidex) {
           _dex_arg_key = "${_rebased_build_config}:dist_jar:dependency_jars"
+          extra_main_dex_proguard_config = _generated_proguard_main_dex_config
+          deps += [ ":$process_resources_target" ]
         } else {
           _dex_arg_key =
               "${_rebased_build_config}:final_dex:dependency_dex_files"
         }
         args = [ "--inputs=@FileArg($_dex_arg_key)" ]
       }
     }
 
     _native_libs_file_arg_dep = ":$build_config_target"
     _native_libs_file_arg = "@FileArg($_rebased_build_config:native:libraries)"
@@ skipping 883 matching lines @@
         # because in practice they seem to contain classes required to be in the
         # classpath.
         deps += _subjar_targets
       }
       if (defined(_res_target_name)) {
         deps += [ ":$_res_target_name" ]
       }
     }
   }
 }