Remove ModalPermissionPrompts from the config and ChromeFeatureList.

Bug: 1126640
Change-Id: I68e843e59e240a597998f7280667e675eded8985
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2426770Reviewed-by: Ilya Sherman <isherman@chromium.org>
Commit-Queue: Caitlin Fischer <caitlinfischer@google.com>
Cr-Commit-Position: refs/heads/master@{#810589}

chrome/browser/flags/android/java/src/org/chromium/chrome/browser/flags/ChromeFeatureList.java

@@ -316,7 +316,6 @@ public abstract class ChromeFeatureList {
     public static final String MESSAGES_FOR_ANDROID_INFRASTRUCTURE =
             "MessagesForAndroidInfrastructure";
     public static final String MOBILE_IDENTITY_CONSISTENCY = "MobileIdentityConsistency";
-    public static final String MODAL_PERMISSION_PROMPTS = "ModalPermissionPrompts";
     public static final String MODAL_PERMISSION_DIALOG_VIEW = "ModalPermissionDialogView";
     public static final String NEW_PHOTO_PICKER = "NewPhotoPicker";
     public static final String NOTIFICATION_SUSPENDER = "NotificationSuspender";

testing/variations/fieldtrial_testing_config.json

@@ -5370,22 +5370,6 @@
             ]
         }
     ],
-    "PermissionPromptUIAndroidModal": [
-        {
-            "platforms": [
-                "android",
-                "android_weblayer"
-            ],
-            "experiments": [
-                {
-                    "name": "ModalToggleEnabled",
-                    "enable_features": [
-                        "ModalPermissionPrompts"
-                    ]
-                }
-            ]
-        }
-    ],
     "PermissionPromptUICocoa": [
         {
             "platforms": [