Implement CHA through type mask and TypedSelector in the simple type inferrer.

sdk/lib/_internal/compiler/implementation/ssa/types_propagation.dart

Index: sdk/lib/_internal/compiler/implementation/ssa/types_propagation.dart
===================================================================
--- sdk/lib/_internal/compiler/implementation/ssa/types_propagation.dart	(revision 19670)
+++ sdk/lib/_internal/compiler/implementation/ssa/types_propagation.dart	(working copy)
@@ -129,23 +129,7 @@
     int receiverIndex = instruction.isInterceptorCall ? 1 : 0;
     HType receiverType = instruction.inputs[receiverIndex].instructionType;
     Selector refined = receiverType.refine(instruction.selector, compiler);
-    // TODO(kasperl): Ask the type inferrer about the type of the
-    // selector not the individual elements. This is basically code
-    // lifted out of the inferrer. Not good.
-    HType type = HType.CONFLICTING;
-    DartType functionType = compiler.functionClass.computeType(compiler);
-    for (Element each in compiler.world.allFunctions.filter(refined)) {
-      HType inferred;
-      if (refined.isGetter() && each.isFunction()) {
-        inferred = new HType.nonNullExact(functionType, compiler);
-      } else if (refined.isGetter() && each.isField()) {
-        inferred = new HType.inferredTypeForElement(each, compiler);
-      } else {
-        inferred = new HType.inferredReturnTypeForElement(each, compiler);
-      }
-      type = type.union(inferred, compiler);
-      if (type.isUnknown()) break;
-    }
+    HType type = new HType.inferredTypeForSelector(refined, compiler);
     if (type.isUseful()) return type;
     return instruction.specializer.computeTypeFromInputTypes(
         instruction, compiler);