Don't show donate or research megaphones on new app installs.

app/src/main/java/org/thoughtcrime/securesms/util/VersionTracker.java

@@ -1,12 +1,15 @@
 package org.thoughtcrime.securesms.util;
 
 import android.content.Context;
+import android.content.pm.PackageManager;
+
 import androidx.annotation.NonNull;
 
 import org.thoughtcrime.securesms.keyvalue.SignalStore;
 import org.thoughtcrime.securesms.logging.Log;
 
 import java.io.IOException;
+import java.util.concurrent.TimeUnit;
 
 public class VersionTracker {
 
@@ -30,4 +33,17 @@ public class VersionTracker {
       throw new AssertionError(ioe);
     }
   }
+
+  public static long getDaysSinceFirstInstalled(Context context) {
+    try {
+      long installTimestamp = context.getPackageManager()
+                                     .getPackageInfo(context.getPackageName(), 0)
+                                     .firstInstallTime;
+
+      return TimeUnit.MILLISECONDS.toDays(System.currentTimeMillis() - installTimestamp);
+    } catch (PackageManager.NameNotFoundException e) {
+      Log.w(TAG, e);
+      return 0;
+    }
+  }
 }