[io] Provide dart::bin::SetupDartIoLibrary

Instead of requiring embedder to initialize dart:io by bits and pieces
by invoking various hooks and setting fields provide a structured C++
API for preparing dart:io for execution.

TEST=ci

CoreLibraryReviewExempt: VM specific changes only
Change-Id: I66e95c0a451d384b4f7582d1df059e506a6a6964
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/454062
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Slava Egorov <vegorov@google.com>

runtime/engine/BUILD.gn

@@ -27,7 +27,7 @@ source_set("engine_jit_set") {
 
   deps = [
     "..:libdart_jit",
-    "../bin:dart_io_api",
+    "../bin:common_embedder_dart_io",
     "../bin:dart_kernel_platform_cc",
     "../bin:libdart_builtin",
   ]
@@ -59,7 +59,7 @@ source_set("engine_aot_set") {
 
   deps = [
     "..:libdart_aotruntime",
-    "../bin:dart_io_api",
+    "../bin:common_embedder_dart_io",
     "../bin:libdart_builtin",
   ]
 }

runtime/engine/engine.cc

@@ -194,8 +194,9 @@ Dart_Isolate Engine::StartIsolate(DartEngine_SnapshotData snapshot,
 
   // In fact, this call initializes core libraries, (e.g. `print` doesn't work
   // without it).
-  Dart_Handle core_libs_result = bin::DartUtils::PrepareForScriptLoading(
-      false, false, /*flag_profile_microtasks=*/false);
+  Dart_Handle core_libs_result = bin::DartUtils::SetupCoreLibraries(
+      /*is_service_isolate=*/false, /*trace_loading=*/false,
+      /*flag_profile_microtasks=*/false, bin::DartIoSettings{});
   if (Dart_IsError(core_libs_result)) {
     *error = Utils::StrDup(Dart_GetError(core_libs_result));
     Dart_ShutdownIsolate();