Use backend targets to run Kernel transformations in Fasta

pkg/front_end/lib/src/fasta/kernel/kernel_target.dart

Index: pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart b/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
index b4e3eee32c465142118f3323edb6cc66e165fdad..90d1da8151afb7673ff616e580ad1220ab33fb16 100644
--- a/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/kernel_target.dart
@@ -655,27 +655,11 @@ class KernelTarget extends TargetImplementation {
   /// Run all transformations that are needed when building a program for the
   /// first time.
   void runBuildTransformations() {
-    transformMixinApplications();
-    otherTransformations();
-  }
-
-  void transformMixinApplications() {
-    mix.transformLibraries(
-        backendTarget, loader.coreTypes, loader.hierarchy, loader.libraries);
-    ticker.logMs("Transformed mixin applications");
-  }
-
-  void otherTransformations() {
-    if (!strongMode) {
-      // TODO(ahe): Don't generate type variables in the first place.
-      program.accept(new Erasure());
-      ticker.logMs("Erased type variables in generic methods");
-    }
-    if (errors.isEmpty && loader.collectCompileTimeErrors().isEmpty) {
-      // TODO(kmillikin): Make this run on a per-method basis.
-      transformAsync.transformLibraries(loader.coreTypes, loader.libraries);
-    }
-    ticker.logMs("Transformed async methods");
+    backendTarget.performModularTransformationsOnLibraries(
+        loader.coreTypes, loader.hierarchy, loader.libraries,
+        logger: (String msg) => ticker.logMs(msg));
+    backendTarget.performGlobalTransformations(loader.coreTypes, program,
+        logger: (String msg) => ticker.logMs(msg));
   }
 
   void verify() {