[fuchsia] make dart_runner work with cfv2

Adds support for running the dart runner as a CFv2 component.
The runner has been refactored to launch in both a v1 environemnt
as well as a v2 environment.

Author: chaselatta

shell/platform/fuchsia/dart-pkg/fuchsia/sdk_ext/fuchsia.cc

@@ -117,10 +117,13 @@ void Initialize(fidl::InterfaceHandle<fuchsia::sys::Environment> environment,
   dart_state->class_library().add_provider("fuchsia",
                                            std::move(fuchsia_class_provider));
 
-  result = Dart_SetField(
-      library, ToDart("_environment"),
-      ToDart(zircon::dart::Handle::Create(environment.TakeChannel())));
-  FML_CHECK(!tonic::LogIfError(result));
+  // v2 components do not use the environment
+  if (environment) {
+    result = Dart_SetField(
+        library, ToDart("_environment"),
+        ToDart(zircon::dart::Handle::Create(environment.TakeChannel())));
+    FML_CHECK(!tonic::LogIfError(result));
+  }
 
   if (directory_request) {
     result = Dart_SetField(

shell/platform/fuchsia/dart_runner/BUILD.gn

@@ -58,6 +58,7 @@ template("runner") {
              "//flutter/fml",
              "//flutter/shell/platform/fuchsia/dart-pkg/fuchsia",
              "//flutter/shell/platform/fuchsia/dart-pkg/zircon",
+             "$fuchsia_sdk_root/fidl:fuchsia.component.runner",
              "$fuchsia_sdk_root/pkg:async",
              "$fuchsia_sdk_root/pkg:async-cpp",
              "$fuchsia_sdk_root/pkg:async-default",
@@ -209,6 +210,7 @@ template("jit_runner_package") {
     binary = "dart_jit${product_suffix}_runner"
 
     cmx_file = rebase_path("meta/dart_jit${product_suffix}_runner.cmx")
+    cml_file = rebase_path("meta/dart_jit${product_suffix}_runner.cml")
 
     libraries = common_libs