Wires the locale provided by Fuchsia. (#13045)

The FIDL service `fuchsia.intl.PropertyProvider` is a service that
the flutter runner can use to obtain information on system preferred
locales.

This change sends a platform message "setLocale" on the channel
"flutter/localization", based on the values provided by the above
mentioned FIDL service.

Credit: most of this was initially written by @kpozin; I ported it
to out-of-tree flutter engine.

Tested:

1. Compile and publish the unit tests package as shown in
   the script below.
2. In a Fuchsia repository (pointed to by `$FUCHSIA_DIR`), run
   `fx serve`
3. `fx shell run fuchsia-pkg://fuchsia.com/flutter_runner_tests#meta/flutter_runner_tests.cmx`

The script used to update the unit tests.

```bash

set -x

FLUTTER_ENGINE_DIR="${FLUTTER_ENGINE_DIR:-$HOME/fx/flutter/engine/src}"
readonly OUT_DIR="${FLUTTER_ENGINE_DIR}/out"

(
  cd ${FLUTTER_ENGINE_DIR}
  ./flutter/tools/gn --fuchsia --fuchsia-cpu x64 --unoptimized
  ninja -j 100 -C "${OUT_DIR}/fuchsia_debug_unopt_x64"
  cp "${OUT_DIR}/compile_commands.json" "${FLUTTER_ENGINE_DIR}"

  echo "Publishing the tests package"
  "${FLUTTER_ENGINE_DIR}/fuchsia/sdk/linux/tools/pm" publish \
    -a -r $FUCHSIA_DIR/out/release/amber-files \
    -f "${FLUTTER_ENGINE_DIR}/out/fuchsia_debug_unopt_x64/flutter_runner_tests-0.far"
)
```

ci/licenses_golden/licenses_flutter

@@ -951,6 +951,9 @@ FILE: ../../../flutter/shell/platform/fuchsia/flutter/compositor_context.h
 FILE: ../../../flutter/shell/platform/fuchsia/flutter/engine.cc
 FILE: ../../../flutter/shell/platform/fuchsia/flutter/engine.h
 FILE: ../../../flutter/shell/platform/fuchsia/flutter/flutter_runner_fakes.h
+FILE: ../../../flutter/shell/platform/fuchsia/flutter/fuchsia_intl.cc
+FILE: ../../../flutter/shell/platform/fuchsia/flutter/fuchsia_intl.h
+FILE: ../../../flutter/shell/platform/fuchsia/flutter/fuchsia_intl_unittest.cc
 FILE: ../../../flutter/shell/platform/fuchsia/flutter/isolate_configurator.cc
 FILE: ../../../flutter/shell/platform/fuchsia/flutter/isolate_configurator.h
 FILE: ../../../flutter/shell/platform/fuchsia/flutter/kernel/extract_far.dart

shell/platform/fuchsia/flutter/BUILD.gn

@@ -256,6 +256,9 @@ executable("flutter_runner_unittests") {
     "accessibility_bridge.h",
     "accessibility_bridge_unittest.cc",
     "flutter_runner_fakes.h",
+    "fuchsia_intl.cc",
+    "fuchsia_intl.h",
+    "fuchsia_intl_unittest.cc",
     "logging.h",
     "platform_view.cc",
     "platform_view.h",
@@ -298,6 +301,13 @@ fuchsia_archive("flutter_runner_tests") {
 
   binary = "$target_name"
 
+  resources = [
+    {
+      path = rebase_path("//third_party/icu/common/icudtl.dat")
+      dest = "icudtl.dat"
+    },
+  ]
+
   meta_dir = "$flutter_root/shell/platform/fuchsia/flutter/meta"
 
   libraries = common_libs

shell/platform/fuchsia/flutter/engine.cc

@@ -5,6 +5,7 @@
 #include "engine.h"
 
 #include <lib/async/cpp/task.h>
+#include <zircon/status.h>
 #include <sstream>
 
 #include "flutter/common/task_runners.h"
@@ -14,6 +15,7 @@
 #include "flutter/runtime/dart_vm_lifecycle.h"
 #include "flutter/shell/common/rasterizer.h"
 #include "flutter/shell/common/run_configuration.h"
+#include "fuchsia_intl.h"
 #include "platform_view.h"
 #include "runtime/dart/utils/files.h"
 #include "task_runner_adapter.h"
@@ -39,6 +41,13 @@ static void UpdateNativeThreadLabelNames(const std::string& label,
   set_thread_name(runners.GetIOTaskRunner(), label, ".io");
 }
 
+static fml::RefPtr<flutter::PlatformMessage> MakeLocalizationPlatformMessage(
+    const fuchsia::intl::Profile& intl_profile) {
+  return fml::MakeRefCounted<flutter::PlatformMessage>(
+      "flutter/localization", MakeLocalizationPlatformMessageData(intl_profile),
+      nullptr);
+}
+
 Engine::Engine(Delegate& delegate,
                std::string thread_label,
                std::shared_ptr<sys::ServiceDirectory> svc,
@@ -110,8 +119,7 @@ Engine::Engine(Delegate& delegate,
       on_create_platform_view = fml::MakeCopyable(
           [debug_label = thread_label_,
            view_ref_control = std::move(view_ref_control),
-           view_ref = std::move(view_ref),
-           runner_services = std::move(runner_services),
+           view_ref = std::move(view_ref), runner_services,
            parent_environment_service_provider =
                std::move(parent_environment_service_provider),
            session_listener_request = std::move(session_listener_request),
@@ -255,6 +263,49 @@ Engine::Engine(Delegate& delegate,
   //  notification. Fire one eagerly.
   shell_->GetPlatformView()->NotifyCreated();
 
+  // Connect to the intl property provider.
+  {
+    intl_property_provider_.set_error_handler([](zx_status_t status) {
+      FML_LOG(ERROR) << "Failed to connect to "
+                     << fuchsia::intl::PropertyProvider::Name_ << ": "
+                     << zx_status_get_string(status);
+    });
+
+    // Note that we're using the runner's services, not the component's.
+    // Flutter locales should be updated regardless of whether the component has
+    // direct access to the fuchsia.intl.PropertyProvider service.
+    ZX_ASSERT(runner_services->Connect(intl_property_provider_.NewRequest()) ==
+              ZX_OK);
+
+    auto get_profile_callback = [flutter_runner_engine =
+                                     weak_factory_.GetWeakPtr()](
+                                    const fuchsia::intl::Profile& profile) {
+      if (!flutter_runner_engine) {
+        return;
+      }
+      if (!profile.has_locales()) {
+        FML_LOG(WARNING) << "Got intl Profile without locales";
+      }
+      auto message = MakeLocalizationPlatformMessage(profile);
+      FML_VLOG(-1) << "Sending LocalizationPlatformMessage";
+      flutter_runner_engine->shell_->GetPlatformView()->DispatchPlatformMessage(
+          message);
+    };
+
+    FML_VLOG(-1) << "Requesting intl Profile";
+
+    // Make the initial request
+    intl_property_provider_->GetProfile(get_profile_callback);
+
+    // And register for changes
+    intl_property_provider_.events().OnChange = [this, runner_services,
+                                                 get_profile_callback]() {
+      FML_VLOG(-1) << fuchsia::intl::PropertyProvider::Name_ << ": OnChange";
+      runner_services->Connect(intl_property_provider_.NewRequest());
+      intl_property_provider_->GetProfile(get_profile_callback);
+    };
+  }
+
   // Launch the engine in the appropriate configuration.
   auto run_configuration = flutter::RunConfiguration::InferFromSettings(
       settings_, task_runners.GetIOTaskRunner());

shell/platform/fuchsia/flutter/engine.h

@@ -5,6 +5,7 @@
 #ifndef FLUTTER_SHELL_PLATFORM_FUCHSIA_ENGINE_H_
 #define FLUTTER_SHELL_PLATFORM_FUCHSIA_ENGINE_H_
 
+#include <fuchsia/intl/cpp/fidl.h>
 #include <fuchsia/io/cpp/fidl.h>
 #include <fuchsia/ui/gfx/cpp/fidl.h>
 #include <fuchsia/ui/views/cpp/fidl.h>
@@ -58,6 +59,8 @@ class Engine final {
   std::unique_ptr<flutter::Shell> shell_;
   zx::event vsync_event_;
   fml::WeakPtrFactory<Engine> weak_factory_;
+  // A stub for the FIDL protocol fuchsia.intl.PropertyProvider.
+  fuchsia::intl::PropertyProviderPtr intl_property_provider_;
 
   void OnMainIsolateStart();
 

shell/platform/fuchsia/flutter/engine_flutter_runner.gni

@@ -50,6 +50,8 @@ template("flutter_runner") {
       "compositor_context.h",
       "engine.cc",
       "engine.h",
+      "fuchsia_intl.cc",
+      "fuchsia_intl.h",
       "isolate_configurator.cc",
       "isolate_configurator.h",
       "logging.h",
@@ -111,6 +113,7 @@ template("flutter_runner") {
              "$fuchsia_sdk_root/fidl:fuchsia.accessibility.semantics",
              "$fuchsia_sdk_root/fidl:fuchsia.fonts",
              "$fuchsia_sdk_root/fidl:fuchsia.images",
+             "$fuchsia_sdk_root/fidl:fuchsia.intl",
              "$fuchsia_sdk_root/fidl:fuchsia.io",
              "$fuchsia_sdk_root/fidl:fuchsia.modular",
              "$fuchsia_sdk_root/fidl:fuchsia.sys",

shell/platform/fuchsia/flutter/fuchsia_intl.cc

+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "fuchsia_intl.h"
+
+#include <sstream>
+#include <string>
+#include <vector>
+
+#include "loop.h"
+#include "rapidjson/document.h"
+#include "rapidjson/stringbuffer.h"
+#include "rapidjson/writer.h"
+#include "runner.h"
+#include "runtime/dart/utils/tempfs.h"
+#include "third_party/icu/source/common/unicode/bytestream.h"
+#include "third_party/icu/source/common/unicode/errorcode.h"
+#include "third_party/icu/source/common/unicode/locid.h"
+#include "third_party/icu/source/common/unicode/strenum.h"
+#include "third_party/icu/source/common/unicode/stringpiece.h"
+#include "third_party/icu/source/common/unicode/uloc.h"
+
+using icu::Locale;
+
+namespace flutter_runner {
+
+using fuchsia::intl::Profile;
+
+std::vector<uint8_t> MakeLocalizationPlatformMessageData(
+    const Profile& intl_profile) {
+  rapidjson::Document document;
+  auto& allocator = document.GetAllocator();
+  document.SetObject();
+  document.AddMember("method", "setLocale", allocator);
+  rapidjson::Value args(rapidjson::kArrayType);
+
+  for (const auto& locale_id : intl_profile.locales()) {
+    UErrorCode error_code = U_ZERO_ERROR;
+    icu::Locale locale = icu::Locale::forLanguageTag(locale_id.id, error_code);
+    if (U_FAILURE(error_code)) {
+      FML_LOG(ERROR) << "Error parsing locale ID \"" << locale_id.id << "\"";
+      continue;
+    }
+    args.PushBack(rapidjson::Value().SetString(locale.getLanguage(), allocator),
+                  allocator);
+
+    auto country = locale.getCountry() != nullptr ? locale.getCountry() : "";
+    args.PushBack(rapidjson::Value().SetString(country, allocator), allocator);
+
+    auto script = locale.getScript() != nullptr ? locale.getScript() : "";
+    args.PushBack(rapidjson::Value().SetString(script, allocator), allocator);
+
+    std::string variant =
+        locale.getVariant() != nullptr ? locale.getVariant() : "";
+    // ICU4C capitalizes the variant for backward compatibility, even though
+    // the preferred form is lowercase.  So we lowercase here.
+    std::transform(begin(variant), end(variant), begin(variant),
+                   [](unsigned char c) { return std::tolower(c); });
+    args.PushBack(rapidjson::Value().SetString(variant, allocator), allocator);
+  }
+
+  document.AddMember("args", args, allocator);
+
+  rapidjson::StringBuffer buffer;
+  rapidjson::Writer<rapidjson::StringBuffer> writer(buffer);
+  document.Accept(writer);
+  auto data = reinterpret_cast<const uint8_t*>(buffer.GetString());
+  return std::vector<uint8_t>(data, data + buffer.GetSize());
+}
+
+}  // namespace flutter_runner

shell/platform/fuchsia/flutter/fuchsia_intl.h

+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FLUTTER_SHELL_PLATFORM_FUCHSIA_FUCHSIA_INTL_H_
+#define FLUTTER_SHELL_PLATFORM_FUCHSIA_FUCHSIA_INTL_H_
+
+#include <fuchsia/intl/cpp/fidl.h>
+
+namespace flutter_runner {
+
+// Make a byte vector containing the JSON string used for a localization
+// PlatformMessage, using the locale list in the given Profile.
+//
+// This method does not return a `fml::RefPtr<flutter::PlatformMessage>` for
+// testing convenience; that would require an unreasonably large set of
+// dependencies for the unit tests.
+std::vector<uint8_t> MakeLocalizationPlatformMessageData(
+    const fuchsia::intl::Profile& intl_profile);
+
+}  // namespace flutter_runner
+
+#endif  // FLUTTER_SHELL_PLATFORM_FUCHSIA_FUCHSIA_INTL_H_

shell/platform/fuchsia/flutter/fuchsia_intl_unittest.cc

+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <fuchsia/intl/cpp/fidl.h>
+#include <gtest/gtest.h>
+
+#include "flutter/fml/icu_util.h"
+
+#include "fuchsia_intl.h"
+
+using fuchsia::intl::CalendarId;
+using fuchsia::intl::LocaleId;
+using fuchsia::intl::Profile;
+using fuchsia::intl::TemperatureUnit;
+using fuchsia::intl::TimeZoneId;
+
+namespace flutter_runner {
+namespace {
+
+class FuchsiaIntlTest : public testing::Test {
+ public:
+  static void SetUpTestCase() {
+    testing::Test::SetUpTestCase();
+    // The icudtl data must be present as a resource in the package for this
+    // load to succeed.
+    fml::icu::InitializeICU("/pkg/data/icudtl.dat");
+  }
+};
+
+TEST_F(FuchsiaIntlTest, MakeLocalizationPlatformMessageData_SimpleLocale) {
+  Profile profile{};
+  profile.set_locales({LocaleId{.id = "en-US"}});
+  const std::string expected =
+      R"({"method":"setLocale","args":["en","US","",""]})";
+  const auto actual = MakeLocalizationPlatformMessageData(profile);
+  ASSERT_EQ(expected, std::string(actual.begin(), actual.end()));
+}
+
+TEST_F(FuchsiaIntlTest, MakeLocalizationPlatformMessageData_OneLocale) {
+  Profile profile{};
+  profile
+      .set_locales({LocaleId{.id = "en-US-u-ca-gregory-fw-sun-hc-h12-ms-"
+                                   "ussystem-nu-latn-tz-usnyc"}})
+      .set_calendars({CalendarId{.id = "und-u-gregory"}})
+      .set_time_zones({TimeZoneId{.id = "America/New_York"}})
+      .set_temperature_unit(TemperatureUnit::FAHRENHEIT);
+  const std::string expected =
+      R"({"method":"setLocale","args":["en","US","",""]})";
+  const auto actual = MakeLocalizationPlatformMessageData(profile);
+  ASSERT_EQ(expected, std::string(actual.begin(), actual.end()));
+}
+
+TEST_F(FuchsiaIntlTest, MakeLocalizationPlatformMessageData_MultipleLocales) {
+  Profile profile{};
+  profile
+      .set_locales({LocaleId{.id = "en-US-u-ca-gregory-fw-sun-hc-h12-ms-"
+                                   "ussystem-nu-latn-tz-usnyc"},
+                    LocaleId{.id = "sl-Latn-IT-nedis"},
+                    LocaleId{.id = "zh-Hans"}, LocaleId{.id = "sr-Cyrl-CS"}})
+      .set_calendars({CalendarId{.id = "und-u-gregory"}})
+      .set_time_zones({TimeZoneId{.id = "America/New_York"}})
+      .set_temperature_unit(TemperatureUnit::FAHRENHEIT);
+  const std::string expected =
+      R"({"method":"setLocale","args":["en","US","","","sl","IT","Latn","nedis",)"
+      R"("zh","","Hans","","sr","CS","Cyrl",""]})";
+  const auto actual = MakeLocalizationPlatformMessageData(profile);
+  ASSERT_EQ(expected, std::string(actual.begin(), actual.end()));
+}
+
+}  // namespace
+}  // namespace flutter_runner

shell/platform/fuchsia/flutter/meta/flutter_aot_runner.cmx

@@ -11,10 +11,11 @@
     "services": [
       "fuchsia.accessibility.SettingsManager",
       "fuchsia.accessibility.semantics.SemanticsManager",
-      "fuchsia.device.NameProvider",
       "fuchsia.deprecatedtimezone.Timezone",
+      "fuchsia.device.NameProvider",
       "fuchsia.feedback.CrashReporter",
       "fuchsia.fonts.Provider",
+      "fuchsia.intl.PropertyProvider",
       "fuchsia.net.NameLookup",
       "fuchsia.netstack.Netstack",
       "fuchsia.posix.socket.Provider",

shell/platform/fuchsia/flutter/meta/flutter_jit_runner.cmx

@@ -11,10 +11,11 @@
     "services": [
       "fuchsia.accessibility.SettingsManager",
       "fuchsia.accessibility.semantics.SemanticsManager",
-      "fuchsia.device.NameProvider",
       "fuchsia.deprecatedtimezone.Timezone",
+      "fuchsia.device.NameProvider",
       "fuchsia.feedback.CrashReporter",
       "fuchsia.fonts.Provider",
+      "fuchsia.intl.PropertyProvider",
       "fuchsia.net.NameLookup",
       "fuchsia.netstack.Netstack",
       "fuchsia.posix.socket.Provider",