Add optimizer for trivial functions with wrappers in JS BE

js/js.inliner/src/org/jetbrains/kotlin/js/inline/JsInliner.java

@@ -107,6 +107,7 @@ public class JsInliner extends JsVisitorWithContextImpl {
         for (JsProgramFragment fragment : fragmentsToProcess) {
             JsBlock block = new JsBlock(fragment.getDeclarationBlock(), fragment.getInitializerBlock(), fragment.getExportBlock());
             RemoveUnusedImportsKt.removeUnusedImports(block);
+            SimplifyWrappedFunctionsKt.simplifyWrappedFunctions(block);
             RemoveUnusedFunctionDefinitionsKt.removeUnusedFunctionDefinitions(block, CollectUtilsKt.collectNamedFunctions(block));
         }
     }

js/js.inliner/src/org/jetbrains/kotlin/js/inline/clean/simplifyWrappedFunctions.kt

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.js.inline.clean
+
+import org.jetbrains.kotlin.js.backend.ast.*
+import org.jetbrains.kotlin.js.inline.util.extractFunction
+
+fun simplifyWrappedFunctions(root: JsNode) {
+    val visitor = object : JsVisitorWithContextImpl() {
+        override fun endVisit(x: JsInvocation, ctx: JsContext<in JsNode>) {
+            extractFunction(x)?.let { (function, wrapper) ->
+                if (wrapper != null && wrapper.statements.size == 1) {
+                    ctx.replaceMe(function)
+                }
+            }
+        }
+
+        override fun endVisit(x: JsVars, ctx: JsContext<in JsStatement>) {
+            x.vars.singleOrNull()?.let { jsVar ->
+                (jsVar.initExpression as? JsFunction)?.let { function ->
+                    if (function.name == null) {
+                        function.name = jsVar.name
+                        ctx.replaceMe(function.makeStmt())
+                    }
+                }
+            }
+        }
+    }
+    visitor.accept(root)
+}