Improve 'google-ima3'

Move window.google.ima.dai check at the end of GoogleIma3 function

src/redirects/google-ima3.js

@@ -26,9 +26,7 @@ import {
 export function GoogleIma3(source) {
     const VERSION = '3.453.0';
 
-    // Do not overwrite window.google.ima if it was already set
-    // https://github.com/AdguardTeam/Scriptlets/issues/331
-    const ima = typeof window.google?.ima === 'object' ? window.google.ima : {};
+    const ima = {};
     const AdDisplayContainer = function () { };
     AdDisplayContainer.prototype.destroy = noopFunc;
     AdDisplayContainer.prototype.initialize = noopFunc;
@@ -480,6 +478,14 @@ export function GoogleIma3(source) {
         window.google = {};
     }
 
+    // To avoid conflicts with the DAI SDK, we need to make sure that the
+    // google.ima.dai namespace is not overwritten.
+    // https://github.com/AdguardTeam/Scriptlets/issues/331
+    if (window.google.ima?.dai) {
+        // TODO: Later we should create a mock for the DAI SDK as well.
+        ima.dai = window.google.ima.dai;
+    }
+
     window.google.ima = ima;
 
     hit(source);

tests/redirects/google-ima3.test.js

@@ -99,6 +99,7 @@ test('Ima - check if google.ima.dai was NOT overwritten', (assert) => {
                     StreamManager() { },
                 },
             },
+            shouldBeDiscarded: true,
         },
     };
 
@@ -116,6 +117,13 @@ test('Ima - check if google.ima.dai was NOT overwritten', (assert) => {
         typeof window.google.ima.dai.api.StreamManager === 'function',
         'window.google.ima.dai.api.StreamManager was not overwritten',
     );
+
+    // Only google.ima.dai should not be overwritten
+    assert.strictEqual(
+        window.google.ima.shouldBeDiscarded, undefined,
+        'google.ima.shouldBeDiscarded is undefined',
+    );
+
     AdsLoader.requestAds();
     requestAnimationFrame(() => {
         assert.strictEqual(number, 1, 'number is equal to 1');