Revert "Move Arrays class to private library."

sdk/lib/_internal/compiler/implementation/lib/js_array.dart

Index: sdk/lib/_internal/compiler/implementation/lib/js_array.dart
diff --git a/sdk/lib/_internal/compiler/implementation/lib/js_array.dart b/sdk/lib/_internal/compiler/implementation/lib/js_array.dart
index 9b73f4080cbd0388225a53463aec53ec2e9cfde1..70e47d640aa25f6cb9a412a9c71f738610f5ebba 100644
--- a/sdk/lib/_internal/compiler/implementation/lib/js_array.dart
+++ b/sdk/lib/_internal/compiler/implementation/lib/js_array.dart
@@ -156,30 +156,7 @@ class JSArray<E> implements List<E> {
 
   void insertRange(int start, int length, [E initialValue]) {
     checkGrowable(this, 'insertRange');
-    if (length == 0) {
-      return;
-    }
-    if (length is !int) throw new ArgumentError(length);
-    if (length < 0) throw new ArgumentError(length);
-    if (start is !int) throw new ArgumentError(start);
-
-    var receiver = this;
-    var receiverLength = receiver.length;
-    if (start < 0 || start > receiverLength) {
-      throw new RangeError.value(start);
-    }
-    receiver.length = receiverLength + length;
-    Arrays.copy(receiver,
-                start,
-                receiver,
-                start + length,
-                receiverLength - start);
-    if (initialValue != null) {
-      for (int i = start; i < start + length; i++) {
-        receiver[i] = initialValue;
-      }
-    }
-    receiver.length = receiverLength + length;
+    return listInsertRange(this, start, length, initialValue);
   }
 
   E get first {
@@ -229,7 +206,21 @@ class JSArray<E> implements List<E> {
 
   void setRange(int start, int length, List<E> from, [int startFrom = 0]) {
     checkMutable(this, 'set range');
-    IterableMixinWorkaround.setRangeList(this, start, length, from, startFrom);
+    if (length == 0) return;
+    checkNull(start); // TODO(ahe): This is not specified but co19 tests it.
+    checkNull(length); // TODO(ahe): This is not specified but co19 tests it.
+    checkNull(from); // TODO(ahe): This is not specified but co19 tests it.
+    checkNull(startFrom); // TODO(ahe): This is not specified but co19 tests it.
+    if (start is !int) throw new ArgumentError(start);
+    if (length is !int) throw new ArgumentError(length);
+    if (startFrom is !int) throw new ArgumentError(startFrom);
+    if (length < 0) throw new ArgumentError(length);
+    if (start < 0) throw new RangeError.value(start);
+    if (start + length > this.length) {
+      throw new RangeError.value(start + length);
+    }
+
+    Arrays.copy(from, startFrom, this, start, length);
   }
 
   bool any(bool f(E element)) => IterableMixinWorkaround.any(this, f);
@@ -244,11 +235,13 @@ class JSArray<E> implements List<E> {
   }
 
   int indexOf(E element, [int start = 0]) {
-    return IterableMixinWorkaround.indexOfList(this, element, start);
+    if (start is !int) throw new ArgumentError(start);
+    return Arrays.indexOf(this, element, start, length);
   }
 
   int lastIndexOf(E element, [int start]) {
-    return IterableMixinWorkaround.lastIndexOfList(this, element, start);
+    if (start == null) start = this.length - 1;
+    return Arrays.lastIndexOf(this, element, start);
   }
 
   bool contains(E other) {