Use custom tabs as view whenever possible

app/src/main/java/eu/faircode/email/ActivityBilling.java

@@ -118,7 +118,7 @@ abstract class ActivityBilling extends ActivityBase implements PurchasesUpdatedL
             if (responseCode != BillingClient.BillingResponse.OK)
                 Snackbar.make(getView(), text, Snackbar.LENGTH_LONG).show();
         } else
-            startActivity(getIntentPro());
+            Helper.view(this, getIntentPro());
     }
 
     private void onActivatePro(Intent intent) {

app/src/main/java/eu/faircode/email/ActivityView.java

@@ -548,7 +548,7 @@ public class ActivityView extends ActivityBilling implements FragmentManager.OnB
                             .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
                                 @Override
                                 public void onClick(DialogInterface dialog, int which) {
-                                    startActivity(update);
+                                    Helper.view(ActivityView.this, update);
                                 }
                             })
                             .show();
@@ -624,7 +624,7 @@ public class ActivityView extends ActivityBilling implements FragmentManager.OnB
     }
 
     private void onMenuFAQ() {
-        startActivity(getIntentFAQ());
+        Helper.view(this, getIntentFAQ());
     }
 
     private void onMenuPro() {
@@ -634,7 +634,7 @@ public class ActivityView extends ActivityBilling implements FragmentManager.OnB
     }
 
     private void onMenuPrivacy() {
-        startActivity(getIntentPrivacy());
+        Helper.view(this, getIntentPrivacy());
     }
 
     private void onMenuAbout() {
@@ -646,20 +646,20 @@ public class ActivityView extends ActivityBilling implements FragmentManager.OnB
     private void onMenuRate() {
         Intent faq = getIntentFAQ();
         if (faq.resolveActivity(getPackageManager()) == null)
-            startActivity(getIntentRate());
+            Helper.view(this, getIntentRate());
         else {
             new AlertDialog.Builder(this)
                     .setMessage(R.string.title_issue)
                     .setPositiveButton(R.string.title_yes, new DialogInterface.OnClickListener() {
                         @Override
                         public void onClick(DialogInterface dialog, int which) {
-                            startActivity(getIntentFAQ());
+                            Helper.view(ActivityView.this, getIntentFAQ());
                         }
                     })
                     .setNegativeButton(R.string.title_no, new DialogInterface.OnClickListener() {
                         @Override
                         public void onClick(DialogInterface dialog, int which) {
-                            startActivity(getIntentRate());
+                            Helper.view(ActivityView.this, getIntentRate());
                         }
                     })
                     .show();
@@ -667,7 +667,7 @@ public class ActivityView extends ActivityBilling implements FragmentManager.OnB
     }
 
     private void onMenuOtherApps() {
-        startActivity(getIntentOtherApps());
+        Helper.view(this, getIntentOtherApps());
     }
 
     private class DrawerItem {

app/src/main/java/eu/faircode/email/AdapterAttachment.java

@@ -180,7 +180,7 @@ public class AdapterAttachment extends RecyclerView.Adapter<AdapterAttachment.Vi
                         return;
                     }
 
-                    context.startActivity(intent);
+                    Helper.view(context, intent);
                 } else {
                     if (attachment.progress == null) {
                         Bundle args = new Bundle();

app/src/main/java/eu/faircode/email/Helper.java

@@ -22,6 +22,7 @@ package eu.faircode.email;
 import android.accounts.Account;
 import android.accounts.AccountManager;
 import android.content.Context;
+import android.content.Intent;
 import android.content.res.TypedArray;
 import android.net.Uri;
 import android.preference.PreferenceManager;
@@ -77,7 +78,17 @@ public class Helper {
         }
     };
 
+    static void view(Context context, Intent intent) {
+        Uri uri = intent.getData();
+        if ("http".equals(uri.getScheme()) || "https".equals(uri.getScheme()))
+            view(context, intent.getData());
+        else
+            context.startActivity(intent);
+    }
+
     static void view(Context context, Uri uri) {
+        Log.i(Helper.TAG, "Custom tab=" + uri);
+
         // https://developer.chrome.com/multidevice/android/customtabs
         CustomTabsIntent.Builder builder = new CustomTabsIntent.Builder();
         builder.setToolbarColor(Helper.resolveColor(context, R.attr.colorPrimary));