Remove ChromeActivity usage from AddToHomescreenCoordinator

Cast the activity to a ModalDialogManagerHolder to get the
ModalDialogManager.

Bug: 1155804
Change-Id: Ieae4f796f3e7b93b670ff6e5b8e2a120f2da1c8e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2633363Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Reviewed-by: Peter Conn <peconn@chromium.org>
Commit-Queue: Ella Ge <eirage@chromium.org>
Cr-Commit-Position: refs/heads/master@{#844561}

chrome/android/java/src/org/chromium/chrome/browser/DEPS

@@ -343,9 +343,6 @@ specific_include_rules = {
   "WebappDisclosureController\.java": [
     "+chrome/android/java/src/org/chromium/chrome/browser/app/ChromeActivity.java",
   ],
-  "AddToHomescreenCoordinator\.java": [
-    "+chrome/android/java/src/org/chromium/chrome/browser/app/ChromeActivity.java",
-  ],
   "Fido2CredentialRequest\.java": [
     "+chrome/android/java/src/org/chromium/chrome/browser/app/ChromeActivity.java",
   ],

chrome/android/java/src/org/chromium/chrome/browser/webapps/addtohomescreen/AddToHomescreenCoordinator.java

@@ -13,7 +13,6 @@ import androidx.annotation.VisibleForTesting;
 
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
-import org.chromium.chrome.browser.app.ChromeActivity;
 import org.chromium.chrome.browser.banners.AppBannerManager;
 import org.chromium.chrome.browser.flags.ChromeFeatureList;
 import org.chromium.chrome.browser.tab.Tab;
@@ -24,6 +23,7 @@ import org.chromium.chrome.browser.webapps.PwaBottomSheetControllerProvider;
 import org.chromium.content_public.browser.WebContents;
 import org.chromium.ui.base.WindowAndroid;
 import org.chromium.ui.modaldialog.ModalDialogManager;
+import org.chromium.ui.modaldialog.ModalDialogManagerHolder;
 import org.chromium.ui.modelutil.PropertyModel;
 import org.chromium.ui.modelutil.PropertyModelChangeProcessor;
 
@@ -100,9 +100,11 @@ public class AddToHomescreenCoordinator {
         if (windowAndroid == null) return 0;
 
         Activity activity = windowAndroid.getActivity().get();
-        if (activity == null || !(activity instanceof ChromeActivity)) return 0;
+        if (!(activity instanceof ModalDialogManagerHolder)) return 0;
+
+        ModalDialogManager modalDialogManager =
+                ((ModalDialogManagerHolder) activity).getModalDialogManager();
 
-        ModalDialogManager modalDialogManager = ((ChromeActivity) activity).getModalDialogManager();
         if (modalDialogManager == null) return 0;
 
         AddToHomescreenCoordinator coordinator =