window.addEventListener("load", function () {

if (!window.testRunner || !window.sessionStorage)

return;

if (!window.targetScaleFactor)

window.targetScaleFactor = 2;

var needsBackingScaleFactorChange = window.targetScaleFactor != 1 && !sessionStorage.pageReloaded;

if (needsBackingScaleFactorChange) {

testRunner.waitUntilDone();

testRunner.setBackingScaleFactor(targetScaleFactor, function() {

// Right now there is a bug that srcset does not properly deal with dynamic changes to the scale factor,

// so to work around that, we must reload the page to get the new image.

sessionStorage.pageReloaded = true;

setTimeout(function() { document.location.reload(true) }, 0);

});

return;

}

try {

if (window.runTest)

runTest();

} catch (ex) {

testFailed("Uncaught exception" + ex);

}

var didReload = sessionStorage.pageReloaded;

delete sessionStorage.pageReloaded;

if (didReload)

testRunner.notifyDone();

});