[Android] Remove most resource names in resources.arsc

resource names are stored in the resources.arsc file to allow for
getIdentifier with the string name of the resource to work. This cl
obfuscates all of those resources to one name (and thus stored only
once) for all resources that are not accessed via getIdentifier.

This improves binary size by about 200KB.

Bug: 894208

Change-Id: I28c440c22b90cd045f53017073fdb88c7410d530
Reviewed-on: https://chromium-review.googlesource.com/c/1265897
Commit-Queue: Mohamed Heikal <mheikal@chromium.org>
Reviewed-by: Richard Coles <torne@chromium.org>
Reviewed-by: agrieve <agrieve@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603229}

android_webview/aapt2.config

+string/license_activity_title#no_obfuscate

android_webview/apk/java/src/com/android/webview/chromium/LicenseActivity.java

@@ -29,6 +29,9 @@ public class LicenseActivity extends Activity {
                 String.format("content://%s.%s", packageName, LICENSES_URI_SUFFIX);
         intent.setDataAndType(Uri.parse(licenseUri), LICENSES_CONTENT_TYPE);
         intent.addCategory(Intent.CATEGORY_DEFAULT);
+        // Resources are accessed via getIdentifier because resource ids in the standalone system
+        // webview apk have incorrect package_ids. Accessing resources via getIdentifier needs to be
+        // whitelisted in //android_webview/aapt2.config. see https://crbug.com/894208
         final int titleId =
                 getResources().getIdentifier("license_activity_title", "string", packageName);
         if (titleId != 0) {

build/android/gyp/apkbuilder.py

@@ -327,8 +327,9 @@ def main(args):
         resource_infos = resource_apk.infolist()
 
         # 1. AndroidManifest.xml
-        assert resource_infos[0].filename == 'AndroidManifest.xml'
-        copy_resource(resource_infos[0], out_dir=apk_manifest_dir)
+        copy_resource(
+            resource_apk.getinfo('AndroidManifest.xml'),
+            out_dir=apk_manifest_dir)
 
         # 2. Assets
         if options.write_asset_list:
@@ -376,7 +377,8 @@ def main(args):
           build_utils.AddToZipHermetic(out_apk, apk_path, data='')
 
         # 5. Resources
-        for info in resource_infos[1:]:
+        for info in resource_infos:
+          if info.filename != 'AndroidManifest.xml':
             copy_resource(info)
 
         # 6. Java resources that should be accessible via

build/android/gyp/compile_resources.py

@@ -141,6 +141,17 @@ def _ParseArgs(args):
                           action='store_true',
                           help='Whether to strip xml namespaces from processed '
                                'xml resources')
+  input_opts.add_argument(
+      '--resources-config-path', help='Path to aapt2 resources config file.')
+  input_opts.add_argument(
+      '--optimize-resources',
+      default=False,
+      action='store_true',
+      help='Whether to run the `aapt2 optimize` step on the resources.')
+  input_opts.add_argument(
+      '--unoptimized-resources-path',
+      help='Path to output the intermediate apk before running '
+      '`aapt2 optimize`.')
 
   input_opts.add_argument(
       '--check-resources-pkg-id', type=_PackageIdArgument,
@@ -306,7 +317,6 @@ def _CreateLinkApkArgs(options):
     '--version-name', options.version_name,
     '--auto-add-overlay',
     '--no-version-vectors',
-    '-o', options.apk_path,
   ]
 
   for j in options.include_resources:
@@ -481,7 +491,11 @@ def _CompileDeps(aapt2_path, dep_subdirs, temp_dir):
     partial_path = os.path.join(partials_dir, dirname + '.zip')
     compile_command = (partial_compile_command +
                        ['--dir', directory, '-o', partial_path])
-    build_utils.CheckOutput(compile_command)
+    build_utils.CheckOutput(
+        compile_command,
+        stderr_filter=lambda output:
+            build_utils.FilterLines(
+                output, r'ignoring configuration .* for styleable'))
 
     # Sorting the files in the partial ensures deterministic output from the
     # aapt2 link step which uses order of files in the partial.
@@ -541,7 +555,15 @@ def _PackageApk(options, dep_subdirs, temp_dir, gen_dir, r_txt_path):
   for directory in dep_subdirs:
     renamed_paths.update(_MoveImagesToNonMdpiFolders(directory))
 
+  if options.optimize_resources:
+    if options.unoptimized_resources_path:
+      unoptimized_apk_path = options.unoptimized_resources_path
+    else:
+      unoptimized_apk_path = os.path.join(gen_dir, 'intermediate.ap_')
+  else:
+    unoptimized_apk_path = options.apk_path
   link_command = _CreateLinkApkArgs(options)
+  link_command += ['-o', unoptimized_apk_path]
   link_command += ['--output-text-symbols', r_txt_path]
   # TODO(digit): Is this below actually required for R.txt generation?
   link_command += ['--java', gen_dir]
@@ -557,6 +579,26 @@ def _PackageApk(options, dep_subdirs, temp_dir, gen_dir, r_txt_path):
   # Also creates R.txt
   build_utils.CheckOutput(
       link_command, print_stdout=False, print_stderr=False)
+
+  if options.optimize_resources:
+    # Optimize the resources.arsc file by obfuscating resource names and only
+    # allow usage via R.java constant.
+    optimize_command = [
+        options.aapt2_path,
+        'optimize',
+        '--enable-resource-obfuscation',
+        '-o',
+        options.apk_path,
+        unoptimized_apk_path,
+    ]
+    if options.resources_config_path:
+      optimize_command += [
+          '--resources-config-path',
+          options.resources_config_path,
+      ]
+    build_utils.CheckOutput(
+        optimize_command, print_stdout=False, print_stderr=False)
+
   _CreateResourceInfoFile(
       renamed_paths, options.apk_info_path, options.dependencies_res_zips)
 
@@ -645,6 +687,7 @@ def main(args):
       options.srcjar_out,
       options.proguard_file,
       options.proguard_file_main_dex,
+      options.unoptimized_resources_path,
   ]
   output_paths = [x for x in possible_output_paths if x]
 
@@ -658,6 +701,7 @@ def main(args):
       str(options.png_to_webp),
       str(options.support_zh_hk),
       str(options.no_xml_namespaces),
+      str(options.optimize_resources),
   ]
 
   input_strings.extend(_CreateLinkApkArgs(options))
@@ -674,6 +718,7 @@ def main(args):
       options.android_manifest,
       debug_temp_resources_dir,
       options.shared_resources_whitelist,
+      options.resources_config_path,
   ]
   possible_input_paths += options.include_resources
   input_paths = [x for x in possible_input_paths if x]

build/android/gyp/create_app_bundle.py

@@ -50,6 +50,10 @@ def _ParseArgs(args):
                       help='Output bundle zip archive.')
   parser.add_argument('--module-zips', required=True,
                       help='GN-list of module zip archives.')
+  parser.add_argument(
+      '--rtxt-in-paths', action='append', help='GN-list of module R.txt files.')
+  parser.add_argument(
+      '--rtxt-out-path', help='Path to combined R.txt file for bundle.')
   parser.add_argument('--uncompressed-assets', action='append',
                       help='GN-list of uncompressed assets.')
   parser.add_argument('--uncompress-shared-libraries', action='append',
@@ -63,6 +67,7 @@ def _ParseArgs(args):
 
   options = parser.parse_args(args)
   options.module_zips = build_utils.ParseGnList(options.module_zips)
+  options.rtxt_in_paths = build_utils.ExpandFileArgs(options.rtxt_in_paths)
 
   if len(options.module_zips) == 0:
     raise Exception('The module zip list cannot be empty.')
@@ -285,6 +290,14 @@ def main(args):
 
     shutil.move(tmp_bundle, options.out_bundle)
 
+  if options.rtxt_out_path:
+    with open(options.rtxt_out_path, 'w') as rtxt_out:
+      for rtxt_in_path in options.rtxt_in_paths:
+        with open(rtxt_in_path, 'r') as rtxt_in:
+          rtxt_out.write('-- Contents of {}\n'.format(
+              os.path.basename(rtxt_in_path)))
+          rtxt_out.write(rtxt_in.read())
+
 
 if __name__ == '__main__':
   main(sys.argv[1:])

build/android/gyp/write_build_config.py

@@ -348,6 +348,10 @@ dependencies for this APK.
 The path of an zip archive containing the APK's resources compiled to the
 protocol buffer format (instead of regular binary xml + resources.arsc).
 
+* `deps_info['module_rtxt_path']`:
+The path of the R.txt file generated when compiling the resources for the bundle
+module.
+
 * `native['libraries']`
 List of native libraries for the primary ABI to be embedded in this APK.
 E.g. [ "libchrome.so" ] (i.e. this doesn't include any ABI sub-directory
@@ -871,6 +875,9 @@ def main(argv):
   parser.add_option('--apk-proto-resources',
                     help='Path to resources compiled in protocol buffer format '
                          ' for this apk.')
+  parser.add_option(
+      '--module-rtxt-path',
+      help='Path to R.txt file for resources in a bundle module.')
 
   parser.add_option('--generate-markdown-format-doc', action='store_true',
                     help='Dump the Markdown .build_config format documentation '
@@ -919,6 +926,10 @@ def main(argv):
     if options.type != 'android_app_bundle_module':
       raise Exception('--apk-proto-resources can only be used with '
                       '--type=android_app_bundle_module')
+  if options.module_rtxt_path:
+    if options.type != 'android_app_bundle_module':
+      raise Exception('--module-rxt-path can only be used with '
+                      '--type=android_app_bundle_module')
 
   is_apk_or_module_target = options.type in ('android_apk',
       'android_app_bundle_module')
@@ -1028,6 +1039,9 @@ def main(argv):
     if options.apk_proto_resources:
       deps_info['proto_resources_path'] = options.apk_proto_resources
 
+    if options.module_rtxt_path:
+      deps_info['module_rtxt_path'] = options.module_rtxt_path
+
   if is_java_target:
     deps_info['requires_android'] = bool(options.requires_android)
     deps_info['supports_android'] = bool(options.supports_android)

build/config/android/internal_rules.gni

@@ -320,6 +320,11 @@ template("write_build_config") {
       args += [ "--apk-proto-resources=$_rebased_proto_resources" ]
     }
 
+    if (defined(invoker.module_rtxt_path)) {
+      _rebased_rtxt_path = rebase_path(invoker.module_rtxt_path, root_build_dir)
+      args += [ "--module-rtxt-path=$_rebased_rtxt_path" ]
+    }
+
     if (defined(invoker.shared_libraries_runtime_deps_file)) {
       # Don't list shared_libraries_runtime_deps_file as an input in order to
       # avoid having to depend on the runtime_deps target. See comment in
@@ -1976,14 +1981,15 @@ if (enable_java_templates) {
       outputs = []
 
       _android_aapt_path = android_default_aapt_path
-      if (_proto_format) {
       _android_aapt2_path = android_sdk_tools_bundle_aapt2
+      if (_proto_format) {
         depfile = "$target_gen_dir/${invoker.target_name}_3.d"
       }
 
       inputs = [
         invoker.build_config,
         _android_aapt_path,
+        _android_aapt2_path,
       ]
 
       _rebased_build_config = rebase_path(invoker.build_config, root_build_dir)
@@ -1994,19 +2000,13 @@ if (enable_java_templates) {
         "--include-resources=@FileArg($_rebased_build_config:android:sdk_jars)",
         "--aapt-path",
         rebase_path(_android_aapt_path, root_build_dir),
+        "--aapt2-path",
+        rebase_path(_android_aapt2_path, root_build_dir),
         "--dependencies-res-zips=@FileArg($_rebased_build_config:resources:dependency_zips)",
         "--extra-res-packages=@FileArg($_rebased_build_config:resources:extra_package_names)",
         "--extra-r-text-files=@FileArg($_rebased_build_config:resources:extra_r_text_files)",
       ]
 
-      if (_proto_format) {
-        inputs += [ _android_aapt2_path ]
-        args += [
-          "--aapt2-path",
-          rebase_path(_android_aapt2_path, root_build_dir),
-        ]
-      }
-
       inputs += [ invoker.android_manifest ]
       args += [
         "--android-manifest",
@@ -2043,6 +2043,25 @@ if (enable_java_templates) {
         ]
       }
 
+      if (defined(invoker.optimize_resources) && invoker.optimize_resources) {
+        args += [ "--optimize-resources" ]
+        if (defined(invoker.resources_config_path)) {
+          inputs += [ invoker.resources_config_path ]
+          args += [
+            "--resources-config-path",
+            rebase_path(invoker.resources_config_path, root_build_dir),
+          ]
+        }
+
+        if (defined(invoker.unoptimized_resources_path)) {
+          args += [
+            "--unoptimized-resources-path",
+            rebase_path(invoker.unoptimized_resources_path, root_build_dir),
+          ]
+          outputs += [ invoker.unoptimized_resources_path ]
+        }
+      }
+
       # Useful to have android:debuggable in the manifest even for Release
       # builds. Just omit it for officai
       if (debuggable_apks) {
@@ -2492,6 +2511,13 @@ if (enable_java_templates) {
           get_label_info(_incremental_compile_resources_target_name,
                          "target_gen_dir") + "/AndroidManifest.xml"
 
+      if (defined(invoker.unoptimized_resources_path)) {
+        _incremental_packaged_resources_path =
+            invoker.unoptimized_resources_path
+      } else {
+        _incremental_packaged_resources_path = invoker.packaged_resources_path
+      }
+
       _rebased_build_config =
           rebase_path(invoker.assets_build_config, root_build_dir)
 
@@ -2502,7 +2528,7 @@ if (enable_java_templates) {
         inputs = [
           _android_manifest,
           invoker.assets_build_config,
-          invoker.packaged_resources_path,
+          _incremental_packaged_resources_path,
         ]
         outputs = [
           # Output the non-compiled manifest for easy debugging (as opposed to
@@ -2517,7 +2543,7 @@ if (enable_java_templates) {
           "--out-manifest",
           rebase_path(_incremental_android_manifest, root_build_dir),
           "--in-apk",
-          rebase_path(invoker.packaged_resources_path, root_build_dir),
+          rebase_path(_incremental_packaged_resources_path, root_build_dir),
           "--out-apk",
           rebase_path(_incremental_compiled_resources_path, root_build_dir),
           "--aapt-path",
@@ -3129,7 +3155,11 @@ if (enable_java_templates) {
                                ])
       }
       if (type == "android_app_bundle_module") {
-        forward_variables_from(invoker, [ "proto_resources_path" ])
+        forward_variables_from(invoker,
+                               [
+                                 "proto_resources_path",
+                                 "module_rtxt_path",
+                               ])
       }
       build_config = _build_config
       is_prebuilt = _is_prebuilt

build/config/android/rules.gni

@@ -1884,6 +1884,10 @@ if (enable_java_templates) {
   #   uncompress_shared_libraries: True if shared libraries should be stored
   #     uncompressed in the APK. Must be unset or true if load_library_from_apk
   #     is set to true.
+  #   optimize_resources: True if resource names should be stripped from the
+  #     resources.arsc file in the apk or module.
+  #   resources_config_path: Path to the aapt2 optimize config file that tags
+  #     resources with acceptable/non-acceptable optimizations.
   template("android_apk_or_module") {
     forward_variables_from(invoker, [ "testonly" ])
 
@@ -1913,10 +1917,11 @@ if (enable_java_templates) {
 
     if (defined(invoker.final_apk_path)) {
       _final_apk_path = invoker.final_apk_path
-    } else if (!_is_bundle_module) {
-      _final_apk_path = "$root_build_dir/apks/${invoker.name}.apk"
     } else {
-      _final_apk_path = "$root_build_dir/bundle_modules/${invoker.name}"
+      _final_apk_path = "$root_build_dir/apks/${invoker.name}.apk"
+    }
+    if (!_is_bundle_module) {
+      _final_rtxt_path = "${_final_apk_path}.R.txt"
     }
     _final_apk_path_no_ext_list =
         process_file_template([ _final_apk_path ],
@@ -2123,7 +2128,16 @@ if (enable_java_templates) {
       _android_sdk_dep = "//third_party/android_tools:android_sdk_java"
     }
 
+    _optimize_resources =
+        defined(invoker.optimize_resources) && invoker.optimize_resources
+    if (_optimize_resources) {
+      _unoptimized_resources_path =
+          "$target_out_dir/$_template_name.unoptimized.ap_"
+    }
+
     _compile_resources_target = "${_template_name}__compile_resources"
+    _compile_resources_rtxt_out =
+        "${target_gen_dir}/${_compile_resources_target}_R.txt"
     compile_resources(_compile_resources_target) {
       forward_variables_from(invoker,
                              [
@@ -2133,6 +2147,7 @@ if (enable_java_templates) {
                                "aapt_locale_whitelist",
                                "resource_blacklist_regex",
                                "resource_blacklist_exceptions",
+                               "resources_config_path",
                                "png_to_webp",
                                "no_xml_namespaces",
                              ])
@@ -2144,12 +2159,16 @@ if (enable_java_templates) {
         post_process_script = invoker.post_process_package_resources_script
       }
       srcjar_path = "${target_gen_dir}/${target_name}.srcjar"
-      r_text_out_path = "${target_gen_dir}/${target_name}_R.txt"
+      r_text_out_path = _compile_resources_rtxt_out
       proguard_file = _generated_proguard_config
       if (_enable_multidex) {
         proguard_file_main_dex = _generated_proguard_main_dex_config
       }
       output = _packaged_resources_path
+      if (_optimize_resources) {
+        optimize_resources = true
+        unoptimized_resources_path = _unoptimized_resources_path
+      }
 
       build_config = _build_config
       deps = _deps + [
@@ -2182,6 +2201,28 @@ if (enable_java_templates) {
       }
     }
 
+    if (!_is_bundle_module) {
+      # Output the R.txt file to a more easily discoverable location for
+      # archiving. This is necessary when stripping resource names so that we
+      # have an archive of resource names to ids for shipped apks (for
+      # debugging purposes). We copy the file rather than change the location
+      # of the original because other targets rely on the location of the R.txt
+      # file.
+      _copy_rtxt_target = "${_template_name}__copy_rtxt"
+      copy(_copy_rtxt_target) {
+        deps = [
+          ":$_compile_resources_target",
+        ]
+        sources = [
+          _compile_resources_rtxt_out,
+        ]
+        outputs = [
+          _final_rtxt_path,
+        ]
+      }
+      _final_deps += [ ":$_copy_rtxt_target" ]
+    }
+
     if (_is_base_module && _is_bundle_module) {
       # Bundle modules have to reference resources from the base module.
       # However, to compile the bundle module's resources we have to give it an
@@ -2365,6 +2406,7 @@ if (enable_java_templates) {
 
       if (_is_bundle_module) {
         proto_resources_path = _packaged_resources_path
+        module_rtxt_path = _compile_resources_rtxt_out
       }
 
       if (!_is_bundle_module) {
@@ -2562,6 +2604,9 @@ if (enable_java_templates) {
         if (_incremental_allowed) {
           android_manifest = _android_manifest
           base_path = _base_path
+          if (_optimize_resources) {
+            unoptimized_resources_path = _unoptimized_resources_path
+          }
         }
 
         # Incremental apk does not use native libs nor final dex.
@@ -2835,6 +2880,7 @@ if (enable_java_templates) {
                                "never_incremental",
                                "no_build_hooks",
                                "no_xml_namespaces",
+                               "optimize_resources",
                                "png_to_webp",
                                "post_process_package_resources_script",
                                "product_version_resources_dep",
@@ -2843,6 +2889,7 @@ if (enable_java_templates) {
                                "proguard_jar_path",
                                "resource_blacklist_regex",
                                "resource_blacklist_exceptions",
+                               "resources_config_path",
                                "secondary_abi_loadable_modules",
                                "secondary_abi_shared_libraries",
                                "secondary_native_lib_placeholders",
@@ -2932,6 +2979,7 @@ if (enable_java_templates) {
                                "native_lib_version_rule",
                                "negative_main_dex_globs",
                                "no_xml_namespaces",
+                               "optimize_resources",
                                "png_to_webp",
                                "product_version_resources_dep",
                                "proguard_configs",
@@ -2939,6 +2987,7 @@ if (enable_java_templates) {
                                "proguard_jar_path",
                                "resource_blacklist_regex",
                                "resource_blacklist_exceptions",
+                               "resources_config_path",
                                "secondary_abi_loadable_modules",
                                "secondary_abi_shared_libraries",
                                "secondary_native_lib_placeholders",
@@ -3856,6 +3905,7 @@ if (enable_java_templates) {
       _all_create_module_targets += [
         ":$_create_module_target",
         _module_build_config_target,
+        "${_module_target}__compile_resources",
       ]
       _all_module_zip_paths += [ _module_zip_path ]
       _all_module_build_configs += [ _module_build_config ]
@@ -3914,6 +3964,7 @@ if (enable_java_templates) {
       deps = _all_create_module_targets + [ ":$_build_config_target" ]
       args = [
         "--out-bundle=$_rebased_bundle_path",
+        "--rtxt-out-path=$_rebased_bundle_path.R.txt",
         "--module-zips=$_all_rebased_module_zip_paths",
       ]
       if (_sign_bundle) {
@@ -3936,6 +3987,8 @@ if (enable_java_templates) {
               "$_rebased_build_config:uncompressed_assets)",
           "--uncompress-shared-libraries=@FileArg(" +
               "$_rebased_build_config:native:uncompress_shared_libraries)",
+          "--rtxt-in-paths=@FileArg(" +
+              "$_rebased_build_config:deps_info:module_rtxt_path)",
         ]
       }
     }

chrome/android/chrome_public_apk_tmpl.gni

@@ -107,6 +107,8 @@ template("chrome_public_common_apk_or_module_tmpl") {
     # Use zh-TW strings for zh-HK (https://crbug.com/780847).
     support_zh_hk = true
 
+    optimize_resources = true
+
     if (defined(shared_libraries) && shared_libraries != []) {
       _native_lib_file =
           rebase_path("$root_gen_dir/CHROME_VERSION.json", root_out_dir)
@@ -227,6 +229,9 @@ template("monochrome_public_common_apk_or_module_tmpl") {
     # Webview supports all locales (has no omitted ones).
     aapt_locale_whitelist = locales
 
+    # Resources config for blocklisting resource names from obfuscation
+    resources_config_path = "//android_webview/aapt2.config"
+
     if (!defined(invoker.target_type) || invoker.target_type == "android_apk") {
       # Incremental install doesn't work for monochrome. See crbug.com/663492.
       never_incremental = true