Remove backend dependency from TypeTestRegistry

pkg/compiler/lib/src/js_backend/backend.dart

Index: pkg/compiler/lib/src/js_backend/backend.dart
diff --git a/pkg/compiler/lib/src/js_backend/backend.dart b/pkg/compiler/lib/src/js_backend/backend.dart
index dae68b71c201b4c8264ab4e9fb8c96e99dc5d009..db1c375fa62fdceca27f2e2dca93471e13d86b67 100644
--- a/pkg/compiler/lib/src/js_backend/backend.dart
+++ b/pkg/compiler/lib/src/js_backend/backend.dart
@@ -367,7 +367,6 @@ class JavaScriptBackend {
       new _RuntimeTypesNeedBuilder();
   RuntimeTypesNeed _rtiNeed;
   final _RuntimeTypes _rti;
-  RuntimeTypesChecks _rtiChecks;
 
   RuntimeTypesEncoder _rtiEncoder;
 
@@ -638,14 +637,8 @@ class JavaScriptBackend {
     return _rtiNeedBuilder;
   }
 
-  RuntimeTypesChecks get rtiChecks {
-    assert(invariant(NO_LOCATION_SPANNABLE, _rtiChecks != null,
-        message: "RuntimeTypesChecks has not been computed yet."));
-    return _rtiChecks;
-  }
-
   RuntimeTypesChecksBuilder get rtiChecksBuilder {
-    assert(invariant(NO_LOCATION_SPANNABLE, _rtiChecks == null,
+    assert(invariant(NO_LOCATION_SPANNABLE, !_rti.rtiChecksBuilderClosed,
         message: "RuntimeTypesChecks has already been computed."));
     return _rti;
   }
@@ -1035,11 +1028,6 @@ class JavaScriptBackend {
     return jsAst.prettyPrint(generatedCode[element], compiler.options);
   }
 
-  /// Called to finalize the [RuntimeTypesChecks] information.
-  void finalizeRti() {
-    _rtiChecks = rtiChecksBuilder.computeRequiredChecks();
-  }
-
   /// Generates the output and returns the total size of the generated code.
   int assembleProgram(ClosedWorld closedWorld) {
     int programSize = emitter.assembleProgram(namer, closedWorld);