minor clean-ups (#2951)

lib/compress.js

@@ -4404,7 +4404,6 @@ merge(Compressor.prototype, {
                     var comp = new Compressor(compressor.options);
                     ast = ast.transform(comp);
                     ast.figure_out_scope(mangle);
-                    base54.reset();
                     ast.compute_char_frequency(mangle);
                     ast.mangle_names(mangle);
                     var fun;

lib/minify.js

@@ -150,7 +150,6 @@ function minify(files, options) {
         if (options.mangle) toplevel.figure_out_scope(options.mangle);
         if (timings) timings.mangle = Date.now();
         if (options.mangle) {
-            base54.reset();
             toplevel.compute_char_frequency(options.mangle);
             toplevel.mangle_names(options.mangle);
         }

lib/scope.js

@@ -401,7 +401,7 @@ AST_Symbol.DEFMETHOD("global", function(){
     return this.definition().global;
 });
 
-AST_Toplevel.DEFMETHOD("_default_mangler_options", function(options) {
+function _default_mangler_options(options) {
     options = defaults(options, {
         eval        : false,
         ie8         : false,
@@ -413,10 +413,10 @@ AST_Toplevel.DEFMETHOD("_default_mangler_options", function(options) {
     // Never mangle arguments
     push_uniq(options.reserved, "arguments");
     return options;
-});
+}
 
 AST_Toplevel.DEFMETHOD("mangle_names", function(options){
-    options = this._default_mangler_options(options);
+    options = _default_mangler_options(options);
 
     // We only need to mangle declaration nodes.  Special logic wired
     // into the code generator will display the mangled name if it's
@@ -506,7 +506,7 @@ AST_Toplevel.DEFMETHOD("find_colliding_names", function(options) {
 AST_Toplevel.DEFMETHOD("expand_names", function(options) {
     base54.reset();
     base54.sort();
-    options = this._default_mangler_options(options);
+    options = _default_mangler_options(options);
     var avoid = this.find_colliding_names(options);
     var cname = 0;
     this.globals.each(rename);
@@ -544,7 +544,8 @@ AST_Sequence.DEFMETHOD("tail_node", function() {
 });
 
 AST_Toplevel.DEFMETHOD("compute_char_frequency", function(options){
-    options = this._default_mangler_options(options);
+    options = _default_mangler_options(options);
+    base54.reset();
     try {
         AST_Node.prototype.print = function(stream, force_parens) {
             this._print(stream, force_parens);

test/run-tests.js

@@ -135,7 +135,6 @@ function run_compress_tests() {
             var output = cmp.compress(input);
             output.figure_out_scope(test.mangle);
             if (test.mangle) {
-                U.base54.reset();
                 output.compute_char_frequency(test.mangle);
                 output.mangle_names(test.mangle);
                 if (test.mangle.properties) {