[ios] Adds Discover testing_config

Bug: 1085419
Change-Id: I545fec75952e76b449179f3ec7e676df16db6bc0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2354602Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#798188}

ios/chrome/browser/ui/content_suggestions/content_suggestions_egtest.mm

@@ -98,6 +98,12 @@ GREYElementInteraction* CellWithMatcher(id<GREYMatcher> matcher) {
 
 #pragma mark - Setup/Teardown
 
+- (AppLaunchConfiguration)appConfigurationForTestCase {
+  AppLaunchConfiguration config;
+  config.features_disabled.push_back(kDiscoverFeedInNtp);
+  return config;
+}
+
 #if defined(CHROME_EARL_GREY_2)
 + (void)setUpForTestCase {
   [super setUpForTestCase];

testing/variations/fieldtrial_testing_config.json

@@ -3503,6 +3503,21 @@
             ]
         }
     ],
+    "IOSDiscoverFeed": [
+        {
+            "platforms": [
+                "ios"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "DiscoverFeedInNtp"
+                    ]
+                }
+            ]
+        }
+    ],
     "IOSDragAndDrop": [
         {
             "platforms": [