Read/apply settings that apply process wide before creating any shell components. (#5203)

Author: chinmaygarde

shell/common/shell.cc

@@ -155,11 +155,47 @@ static void RecordStartupTimestamp() {
   }
 }
 
+// Though there can be multiple shells, some settings apply to all components in
+// the process. These have to be setup before the shell or any of its
+// sub-components can be initialized. In a perfect world, this would be empty.
+// TODO(chinmaygarde): The unfortunate side effect of this call is that settings
+// that cause shell initialization failures will still lead to some of their
+// settings being applied.
+static void PerformInitializationTasks(const blink::Settings& settings) {
+  static std::once_flag gShellSettingsInitialization = {};
+  std::call_once(gShellSettingsInitialization, [&settings] {
+    RecordStartupTimestamp();
+
+    fxl::LogSettings log_settings;
+    log_settings.min_log_level =
+        settings.verbose_logging ? fxl::LOG_INFO : fxl::LOG_ERROR;
+    fxl::SetLogSettings(log_settings);
+
+    if (settings.trace_skia) {
+      InitSkiaEventTracer(settings.trace_skia);
+    }
+
+    if (!settings.skia_deterministic_rendering_on_cpu) {
+      SkGraphics::Init();
+    } else {
+      FXL_DLOG(INFO) << "Skia deterministic rendering is enabled.";
+    }
+
+    if (settings.icu_data_path.size() != 0) {
+      fml::icu::InitializeICU(settings.icu_data_path);
+    } else {
+      FXL_DLOG(WARNING) << "Skipping ICU initialization in the shell.";
+    }
+  });
+}
+
 std::unique_ptr<Shell> Shell::Create(
     blink::TaskRunners task_runners,
     blink::Settings settings,
     Shell::CreateCallback<PlatformView> on_create_platform_view,
     Shell::CreateCallback<Rasterizer> on_create_rasterizer) {
+  PerformInitializationTasks(settings);
+
   auto vm = blink::DartVM::ForProcess(settings);
   FXL_CHECK(vm) << "Must be able to initialize the VM.";
   return Shell::Create(std::move(task_runners),             //
@@ -176,12 +212,7 @@ std::unique_ptr<Shell> Shell::Create(
     fxl::RefPtr<blink::DartSnapshot> isolate_snapshot,
     Shell::CreateCallback<PlatformView> on_create_platform_view,
     Shell::CreateCallback<Rasterizer> on_create_rasterizer) {
-  RecordStartupTimestamp();
-
-  fxl::LogSettings log_settings;
-  log_settings.min_log_level =
-      settings.verbose_logging ? fxl::LOG_INFO : fxl::LOG_ERROR;
-  fxl::SetLogSettings(log_settings);
+  PerformInitializationTasks(settings);
 
   if (!task_runners.IsValid() || !on_create_platform_view ||
       !on_create_rasterizer) {
@@ -219,22 +250,6 @@ Shell::Shell(blink::TaskRunners task_runners, blink::Settings settings)
   FXL_DCHECK(task_runners_.IsValid());
   FXL_DCHECK(task_runners_.GetPlatformTaskRunner()->RunsTasksOnCurrentThread());
 
-  if (settings_.icu_data_path.size() != 0) {
-    fml::icu::InitializeICU(settings_.icu_data_path);
-  } else {
-    FXL_DLOG(WARNING) << "Skipping ICU initialization in the shell.";
-  }
-
-  if (settings_.trace_skia) {
-    InitSkiaEventTracer(settings_.trace_skia);
-  }
-
-  if (!settings_.skia_deterministic_rendering_on_cpu) {
-    SkGraphics::Init();
-  } else {
-    FXL_DLOG(INFO) << "Skia deterministic rendering is enabled.";
-  }
-
   // Install service protocol handlers.
 
   service_protocol_handlers_[blink::ServiceProtocol::kScreenshotExtensionName