Redo "dart2js: Insert HTypeKnown refinement nodes on dominated edges of HPhi nodes."

pkg/compiler/lib/src/ssa/types_propagation.dart

Index: pkg/compiler/lib/src/ssa/types_propagation.dart
diff --git a/pkg/compiler/lib/src/ssa/types_propagation.dart b/pkg/compiler/lib/src/ssa/types_propagation.dart
index 49aa6f99cf3d19f255376d32cdcc2a7465b6ea71..7db5f0521277a5914cb8028552fd1d8f315427c1 100644
--- a/pkg/compiler/lib/src/ssa/types_propagation.dart
+++ b/pkg/compiler/lib/src/ssa/types_propagation.dart
@@ -397,7 +397,12 @@ class SsaTypePropagator extends HBaseVisitor implements OptimizationPhase {
           addDependentInstructionsToWorkList(next);
         }
       } else {
-        bool hasCandidates() => receiver.dominatedUsers(instruction).length > 1;
+        DominatedUses uses;
+        bool hasCandidates() {
+          uses =
+              DominatedUses.of(receiver, instruction, excludeDominator: true);
+          return uses.isNotEmpty;
+        }
 
         if ((receiver.usedBy.length <= _MAX_QUICK_USERS)
             ? (hasCandidates() && computeNewType() != receiverType)
@@ -407,7 +412,7 @@ class SsaTypePropagator extends HBaseVisitor implements OptimizationPhase {
           HTypeKnown converted =
               new HTypeKnown.witnessed(newType, receiver, instruction);
           instruction.block.addBefore(instruction.next, converted);
-          receiver.replaceAllUsersDominatedBy(converted.next, converted);
+          uses.replaceWith(converted);
           addDependentInstructionsToWorkList(converted);
         }
       }