Update SVG tests ahead of offset* removal

third_party/WebKit/LayoutTests/svg/as-iframe/svg-in-iframe.html

Index: third_party/WebKit/LayoutTests/svg/as-iframe/svg-in-iframe.html
diff --git a/third_party/WebKit/LayoutTests/svg/as-iframe/svg-in-iframe.html b/third_party/WebKit/LayoutTests/svg/as-iframe/svg-in-iframe.html
index 5434e57945a9725adb117a80f328752ec9e5fe34..13da0738113934cc75e4076c191081c2ac551f80 100644
--- a/third_party/WebKit/LayoutTests/svg/as-iframe/svg-in-iframe.html
+++ b/third_party/WebKit/LayoutTests/svg/as-iframe/svg-in-iframe.html
@@ -8,12 +8,14 @@
     t = async_test("Test <iframe> and <svg> size");
     function check() {
         var iframe = document.querySelector('iframe');
+        var iframeRect = iframe.getBoundingClientRect();
         var svg = iframe.contentDocument.documentElement;
+        var svgRect = svg.getBoundingClientRect();
 
-        assert_equals(iframe.offsetWidth, 300, "width should be fallback width.");
-        assert_equals(iframe.offsetHeight, 150, "height should be the fallback height 150.");
-        assert_equals(svg.offsetWidth, svg.width.baseVal.value, "width should be what the <svg> requests.");
-        assert_equals(svg.offsetHeight, svg.height.baseVal.value, "height should be what the <svg> requests.");
+        assert_equals(iframeRect.width, 300, "width should be fallback width.");
+        assert_equals(iframeRect.height, 150, "height should be the fallback height 150.");
+        assert_equals(svgRect.width, svg.width.baseVal.value, "width should be what the <svg> requests.");
+        assert_equals(svgRect.height, svg.height.baseVal.value, "height should be what the <svg> requests.");
 
         t.done();
     }