[DevTools] New harness for inspector-protocol layout tests

third_party/WebKit/LayoutTests/inspector-protocol/page/get-layout-metrics.js

Index: third_party/WebKit/LayoutTests/inspector-protocol/page/get-layout-metrics.js
diff --git a/third_party/WebKit/LayoutTests/inspector-protocol/page/get-layout-metrics.js b/third_party/WebKit/LayoutTests/inspector-protocol/page/get-layout-metrics.js
new file mode 100644
index 0000000000000000000000000000000000000000..be11743dc98eb4bba9e2a7dc5589e8879adc5fb6
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/inspector-protocol/page/get-layout-metrics.js
@@ -0,0 +1,21 @@
+(async function(testRunner) {
+  let {page, session, dp} = await testRunner.startHTML(`
+    <style>
+    body {
+        min-height: 2000px;
+    }
+    </style>
+  `, 'Tests that Page.getLayoutMetrics returns reasonable values.');
+
+  session.evaluate('window.scrollTo(0, 200);');
+  var message = await dp.Page.getLayoutMetrics();
+  if (message.error) {
+    testRunner.log(message.error.message);
+    testRunner.completeTest();
+    return;
+  }
+
+  testRunner.logObject(message.result.layoutViewport, 'LayoutViewport: ');
+  testRunner.logObject(message.result.visualViewport, 'VisualViewport: ');
+  testRunner.completeTest();
+})