[DevTools] Migrate inspector-protocol/emulation tests to new harness

third_party/WebKit/LayoutTests/inspector-protocol/emulation/device-scale-not-persistant.js

+(async function(testRunner) {
+  let {page, session, dp} = await testRunner.startURL('../resources/device-scale-not-persistant.html',
+      'Test that srcset does not use wrong image when override scalefactor and then disabled.');
+
+  function getSrcsetImage() {
+    return session.evaluate(`document.getElementById('image-test').currentSrc`);
+  }
+
+  async function setScaleFactor(value) {
+    testRunner.log('Set deviceScaleFactor: ' + value);
+    await dp.Emulation.setDeviceMetricsOverride({
+        deviceScaleFactor: value,
+        width: 1,
+        height: 1,
+        mobile: false,
+        fitWindow: false
+    });
+  }
+
+  async function reloadPage() {
+    testRunner.log('Reloading Page');
+    dp.Page.reload();
+    await dp.Page.onceLoadEventFired();
+    testRunner.log('\nPage reloaded.\n');
+  }
+
+  async function dumpImageSrc() {
+    var src = await getSrcsetImage();
+    var relativeSrc = src.substring(src.lastIndexOf('/resources/'));
+    testRunner.log('Used Image: ' + relativeSrc);
+  }
+
+  dp.Page.enable();
+  var initialImage = await getSrcsetImage();
+
+  await setScaleFactor(1);
+  await reloadPage();
+  await dumpImageSrc();
+
+  await setScaleFactor(2);
+  await reloadPage();
+  await dumpImageSrc();
+
+  testRunner.log('Clear deviceScaleFactor');
+  await dp.Emulation.clearDeviceMetricsOverride();
+  await reloadPage();
+  var value = await getSrcsetImage();
+  var initImageEqCurrentImg = initialImage === value ? 'Yes' : 'No';
+  testRunner.log('Current image src equal initial image: ' + initImageEqCurrentImg);
+
+  testRunner.completeTest();
+})