From 127b419fc158446fc5a22eef9a6287b383d42c65 Mon Sep 17 00:00:00 2001
From: Stephen Adams <sra@google.com>
Date: Thu, 22 Sep 2016 10:36:16 -0700
Subject: [PATCH] Add WhereIterable.map

This makes some nice code improvements for dart2js. dart2js can't
inline the MappedIterable factory constructor and specialize by
optimization, so specializing by hand removes the test "is
EfficientLength" for code like "x.where(f).map(g)".

R=lrn@google.com

Review URL: https://codereview.chromium.org/2354093002 .
---
 sdk/lib/internal/iterable.dart | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sdk/lib/internal/iterable.dart b/sdk/lib/internal/iterable.dart
index 2bedb48e646..0e7b171e260 100644
--- a/sdk/lib/internal/iterable.dart
+++ b/sdk/lib/internal/iterable.dart
@@ -426,6 +426,10 @@ class WhereIterable<E> extends Iterable<E> {
   WhereIterable(this._iterable, bool this._f(E element));
 
   Iterator<E> get iterator => new WhereIterator<E>(_iterable.iterator, _f);
+
+  // Specialization of [Iterable.map] to non-EfficientLength.
+  Iterable/*<T>*/ map/*<T>*/(/*=T*/ f(E element)) =>
+     new MappedIterable<E, dynamic/*=T*/>._(this, f);
 }
 
 class WhereIterator<E> extends Iterator<E> {