[dart2js] Use properties on Closure class for one common case

We can share the properties for single-argument closures by putting
the properties on class Closure. (It is worthwhile to do this for zero
and two argument closures, but we will need to add subclasses. That
will be another CL).

Change-Id: I30027965150f64200396df3d82140fb112b0899f
Reviewed-on: https://dart-review.googlesource.com/c/83640
Reviewed-by: Sigmund Cherem <[email protected]>
Commit-Queue: Stephen Adams <[email protected]>

Author: rakudrama

pkg/compiler/lib/src/js_emitter/startup_emitter/fragment_emitter.dart

@@ -979,15 +979,14 @@ class FragmentEmitter {
     if (cls.superclass == null) {
       // TODO(sra): What is this doing? Document or remove.
       properties
-          .add(new js.Property(js.string("constructor"), classReference(cls)));
-      properties
-          .add(new js.Property(namer.operatorIs(cls.element), js.number(1)));
+          .add(js.Property(js.string("constructor"), classReference(cls)));
+      properties.add(js.Property(namer.operatorIs(cls.element), js.number(1)));
     }
 
     allMethods.forEach((Method method) {
       emitInstanceMethod(method)
           .forEach((js.Expression name, js.Expression code) {
-        var prop = new js.Property(name, code);
+        var prop = js.Property(name, code);
         compiler.dumpInfoTask.registerEntityAst(method.element, prop);
         properties.add(prop);
       });
@@ -997,8 +996,16 @@ class FragmentEmitter {
       // Closures extend a common base class, so we can put properties on the
       // prototype for common values.
 
+      // Closures taking exactly one argument are common.
+      properties.add(js.Property(
+          js.string(namer.callCatchAllName),
+          js.quoteName(
+              namer.getNameForJsGetName(null, JsGetName.CALL_PREFIX1))));
+      properties.add(
+          js.Property(js.string(namer.requiredParameterField), js.number(1)));
+
       // Most closures have no optional arguments.
-      properties.add(new js.Property(
+      properties.add(js.Property(
           js.string(namer.defaultValuesField), new js.LiteralNull()));
     }
 
@@ -1081,12 +1088,22 @@ class FragmentEmitter {
         // complex cases. [forceAdd] might be true when this is fixed.
         bool forceAdd = !method.isClosureCallMethod;
 
-        properties[js.string(namer.callCatchAllName)] = js.quoteName(
-            method.applyIndex == 0
-                ? method.name
-                : method.parameterStubs[method.applyIndex - 1].name);
-        properties[js.string(namer.requiredParameterField)] =
-            js.number(method.requiredParameterCount);
+        // Common case of "call*": "call$1" is stored on the Closure class.
+        if (method.applyIndex != 0 ||
+            method.parameterStubs.isNotEmpty ||
+            method.requiredParameterCount != 1 ||
+            forceAdd) {
+          js.Name applyName = method.applyIndex == 0
+              ? method.name
+              : method.parameterStubs[method.applyIndex - 1].name;
+          properties[js.string(namer.callCatchAllName)] =
+              js.quoteName(applyName);
+        }
+        // Common case of '1' is stored on the Closure class.
+        if (method.requiredParameterCount != 1 || forceAdd) {
+          properties[js.string(namer.requiredParameterField)] =
+              js.number(method.requiredParameterCount);
+        }
 
         js.Expression defaultValues =
             _encodeOptionalParameterDefaultValues(method);

pkg/compiler/lib/src/js_emitter/startup_emitter/model_emitter.dart

@@ -18,6 +18,7 @@ import 'package:js_runtime/shared/embedded_names.dart'
         INTERCEPTORS_BY_TAG,
         IS_HUNK_INITIALIZED,
         IS_HUNK_LOADED,
+        JsGetName,
         LEAF_TAGS,
         MANGLED_GLOBAL_NAMES,
         MANGLED_NAMES,