Add dynamic declaration to CssRectangle width/height setters

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 4725c544f91e63426f25ef3349730abf8a196e2f..9546a9834bbdc6f5de3e5077f3841bde57eda9cf 100644
--- a/sdk/lib/html/dartium/html_dartium.dart
+++ b/sdk/lib/html/dartium/html_dartium.dart
@@ -46572,7 +46572,7 @@ class _ContentCssRect extends CssRect {
    * `height` function in jQuery and the calculated `height` CSS value,
    * converted to a num in pixels.
    */
-  set height(newHeight) {
+  set height(dynamic newHeight) {
     if (newHeight is Dimension) {
       if (newHeight.value < 0) newHeight = new Dimension.px(0);
       _element.style.height = newHeight.toString();
@@ -46592,7 +46592,7 @@ class _ContentCssRect extends CssRect {
    * and the calculated
    * `width` CSS value, converted to a dimensionless num in pixels.
    */
-  set width(newWidth) {
+  set width(dynamic newWidth) {
     if (newWidth is Dimension) {
       if (newWidth.value < 0) newWidth = new Dimension.px(0);
       _element.style.width = newWidth.toString();
@@ -46752,7 +46752,7 @@ abstract class CssRect implements Rectangle<num> {
    *
    * Note that only the content height can actually be set via this method.
    */
-  set height(newHeight) {
+  set height(dynamic newHeight) {
     throw new UnsupportedError("Can only set height for content rect.");
   }
 
@@ -46766,7 +46766,7 @@ abstract class CssRect implements Rectangle<num> {
    *
    * Note that only the content width can be set via this method.
    */
-  set width(newWidth) {
+  set width(dynamic newWidth) {
     throw new UnsupportedError("Can only set width for content rect.");
   }