Revert "estimating parameter types" optimization due to failure on browser

lib/compiler/implementation/ssa/builder.dart

Index: lib/compiler/implementation/ssa/builder.dart
diff --git a/lib/compiler/implementation/ssa/builder.dart b/lib/compiler/implementation/ssa/builder.dart
index a1b0b3afb569a7f4accb42b4c1f0fdfe33130196..7aba3c44accefc88a226b09e8344a2dba8bc4830 100644
--- a/lib/compiler/implementation/ssa/builder.dart
+++ b/lib/compiler/implementation/ssa/builder.dart
@@ -138,7 +138,6 @@ class SsaBuilderTask extends CompilerTask {
   // Loop tracking information.
   final Set<FunctionElement> functionsCalledInLoop;
   final Map<SourceString, Selector> selectorsCalledInLoop;
-  final JavaScriptBackend backend;
 
   String get name() => 'SSA builder';
 
@@ -148,7 +147,6 @@ class SsaBuilderTask extends CompilerTask {
       emitter = backend.emitter,
       functionsCalledInLoop = new Set<FunctionElement>(),
       selectorsCalledInLoop = new Map<SourceString, Selector>(),
-      backend = backend,
       super(backend.compiler);
 
   HGraph build(WorkItem work) {
@@ -173,20 +171,6 @@ class SsaBuilderTask extends CompilerTask {
         inLoop = selector !== null && selector.applies(element, compiler);
       }
       graph.calledInLoop = inLoop;
-
-      // If there is an estimate of the parameter types assume these types when
-      // compiling.
-      List<HType> parameterTypes =
-          backend.optimisticParameterTypesWithRecompilationOnTypeChange(
-              element);
-      if (parameterTypes != null) {
-        FunctionSignature signature = element.computeSignature(compiler);
-        int i = 0;
-        signature.forEachParameter((Element param) {
-          builder.parameters[param].guaranteedType = parameterTypes[i++];
-        });
-      }
-
       if (compiler.tracer.enabled) {
         String name;
         if (element.enclosingElement !== null &&