Fix bad precedence for >>> operator.

lib/compiler/implementation/ssa/codegen.dart

Index: lib/compiler/implementation/ssa/codegen.dart
diff --git a/lib/compiler/implementation/ssa/codegen.dart b/lib/compiler/implementation/ssa/codegen.dart
index bba4c84b24d20d54d0b9aeff979f2d74eedb3cc2..4db186fc3a19e2d12810997f879c1e1b85b3bb9f 100644
--- a/lib/compiler/implementation/ssa/codegen.dart
+++ b/lib/compiler/implementation/ssa/codegen.dart
@@ -1121,8 +1121,11 @@ class SsaCodeGenerator implements HVisitor, HBlockInformationVisitor {
   visitBitInvokeBinary(HBinaryBitOp node, String op) {
     if (node.builtin){
       beginExpression(unsignedShiftPrecedences.precedence);
+      int oldPrecedence = this.expectedPrecedence;
+      this.expectedPrecedence = JSPrecedence.SHIFT_PRECEDENCE;
       visitInvokeBinary(node, op);
       buffer.add(' >>> 0');
+      this.expectedPrecedence = oldPrecedence;
       endExpression(unsignedShiftPrecedences.precedence);
     } else {
       visitInvokeBinary(node, op);
@@ -1145,8 +1148,11 @@ class SsaCodeGenerator implements HVisitor, HBlockInformationVisitor {
   visitBitInvokeUnary(HInvokeUnary node, String op) {
     if (node.builtin){
       beginExpression(unsignedShiftPrecedences.precedence);
+      int oldPrecedence = this.expectedPrecedence;
+      this.expectedPrecedence = JSPrecedence.SHIFT_PRECEDENCE;
       visitInvokeUnary(node, op);
       buffer.add(' >>> 0');
+      this.expectedPrecedence = oldPrecedence;
       endExpression(unsignedShiftPrecedences.precedence);
     } else {
       visitInvokeUnary(node, op);