Moved most of html lib generating scripts into tools.

sdk/lib/html/templates/html/dart2js/impl_MouseEvent.darttemplate

Index: sdk/lib/html/templates/html/dart2js/impl_MouseEvent.darttemplate
diff --git a/sdk/lib/html/templates/html/dart2js/impl_MouseEvent.darttemplate b/sdk/lib/html/templates/html/dart2js/impl_MouseEvent.darttemplate
deleted file mode 100644
index 32ad37d16054ccd793a00869088ed600db8d70ff..0000000000000000000000000000000000000000
--- a/sdk/lib/html/templates/html/dart2js/impl_MouseEvent.darttemplate
+++ /dev/null
@@ -1,48 +0,0 @@
-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-part of html;
-
-/// @domName $DOMNAME
-class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
-  factory $CLASSNAME(String type, Window view, int detail, int screenX,
-      int screenY, int clientX, int clientY, int button, [bool canBubble = true,
-      bool cancelable = true, bool ctrlKey = false, bool altKey = false,
-      bool shiftKey = false, bool metaKey = false,
-      EventTarget relatedTarget = null]) =>
-      _$(CLASSNAME)FactoryProvider.create$CLASSNAME(
-          type, view, detail, screenX, screenY,
-          clientX, clientY, button, canBubble, cancelable,
-          ctrlKey, altKey, shiftKey, metaKey,
-          relatedTarget);
-$!MEMBERS
-
-  int get offsetX {
-  if (JS('bool', '!!#.offsetX', this)) {
-      return JS('int', '#.offsetX', this);
-    } else {
-      // Firefox does not support offsetX.
-      var target = this.target;
-      if (!(target is Element)) {
-        throw new UnsupportedError(
-            'offsetX is only supported on elements');
-      }
-      return this.clientX - this.target.getBoundingClientRect().left;
-    }
-  }
-
-  int get offsetY {
-    if (JS('bool', '!!#.offsetY', this)) {
-      return JS('int', '#.offsetY', this);
-    } else {
-      // Firefox does not support offsetY.
-      var target = this.target;
-      if (!(target is Element)) {
-        throw new UnsupportedError(
-            'offsetY is only supported on elements');
-      }
-      return this.clientY - this.target.getBoundingClientRect().top;
-    }
-  }
-}