Revert "Removed Window.focus and Window.blur as they are no longer recommended."

sdk/lib/html/dartium/html_dartium.dart

Index: sdk/lib/html/dartium/html_dartium.dart
diff --git a/sdk/lib/html/dartium/html_dartium.dart b/sdk/lib/html/dartium/html_dartium.dart
index 4602e3f8c802f31e648b2fdf182d72dd4a65db30..5a056c543886a298b5f595efc47321d61eb3f085 100644
--- a/sdk/lib/html/dartium/html_dartium.dart
+++ b/sdk/lib/html/dartium/html_dartium.dart
@@ -15636,6 +15636,10 @@ class LocalWindow extends EventTarget implements Window {
   String atob(String string) native "DOMWindow_atob_Callback";
 
 
+  /** @domName DOMWindow.blur */
+  void blur() native "DOMWindow_blur_Callback";
+
+
   /** @domName DOMWindow.btoa */
   String btoa(String string) native "DOMWindow_btoa_Callback";
 
@@ -15672,6 +15676,10 @@ class LocalWindow extends EventTarget implements Window {
   bool find(String string, bool caseSensitive, bool backwards, bool wrap, bool wholeWord, bool searchInFrames, bool showDialog) native "DOMWindow_find_Callback";
 
 
+  /** @domName DOMWindow.focus */
+  void focus() native "DOMWindow_focus_Callback";
+
+
   /** @domName DOMWindow.getComputedStyle */
   CSSStyleDeclaration $dom_getComputedStyle(Element element, String pseudoElement) native "DOMWindow_getComputedStyle_Callback";
 
@@ -28661,6 +28669,8 @@ abstract class Window {
   Window get top;
 
   // Methods.
+  void focus();
+  void blur();
   void close();
   void postMessage(var message, String targetOrigin, [List messagePorts = null]);
 }