Refactor the collection of initializer list types

lib/compiler/implementation/ssa/optimize.dart

Index: lib/compiler/implementation/ssa/optimize.dart
diff --git a/lib/compiler/implementation/ssa/optimize.dart b/lib/compiler/implementation/ssa/optimize.dart
index 3e7405fa1828b7ef27dce927c272ba4d51d6cebb..e407ecd13bfb66f7995ea2b645dda3d5de537909 100644
--- a/lib/compiler/implementation/ssa/optimize.dart
+++ b/lib/compiler/implementation/ssa/optimize.dart
@@ -1200,19 +1200,19 @@ class SsaProcessRecompileCandidates
         Type type = left.receiver.propagatedType.computeType(compiler);
         switch (compiler.phase) {
           case Compiler.PHASE_COMPILING:
-            if (compiler.codegenWorld.couldHaveFieldOnlyIntegerSetters(
+            if (backend.couldHaveFieldOnlyIntegerSetters(
                     type, left.element.name) &&
-                compiler.codegenWorld.hasFieldOnlyIntegerInitializers(
-                    type, left.element.name)) {
+                backend.couldHaveFieldSingleTypeInitializers(
+                    type, left.element.name, HType.INTEGER)) {
               compiler.enqueuer.codegen.registerRecompilationCandidate(
                   work.element);
             }
             break;
           case Compiler.PHASE_RECOMPILING:
-            if (compiler.codegenWorld.hasFieldOnlyIntegerSetters(
+            if (backend.hasFieldOnlyIntegerSetters(
                     type, left.element.name) &&
-                compiler.codegenWorld.hasFieldOnlyIntegerInitializers(
-                    type, left.element.name)) {
+                backend.hasFieldSingleTypeInitializers(
+                    type, left.element.name, HType.INTEGER)) {
               if (compiler.codegenWorld.hasInvokedSetter(left.element,
                                                          compiler)) {
                 // If there are invoked setters we don't know for sure that the