Merge pull request #5418 from Isira-Seneviratne/Unify_constants

Combine the two Constants files into one file.

app/src/main/java/org/schabi/newpipe/util/Constants.kt

@@ -0,0 +1,20 @@
+@file:JvmName("Constants")
+
+package org.schabi.newpipe.util
+
+/**
+ * Default duration when using throttle functions across the app, in milliseconds.
+ */
+const val DEFAULT_THROTTLE_TIMEOUT = 120L
+
+const val KEY_SERVICE_ID = "key_service_id"
+const val KEY_URL = "key_url"
+const val KEY_TITLE = "key_title"
+const val KEY_LINK_TYPE = "key_link_type"
+const val KEY_OPEN_SEARCH = "key_open_search"
+const val KEY_SEARCH_STRING = "key_search_string"
+
+const val KEY_THEME_CHANGE = "key_theme_change"
+const val KEY_MAIN_PAGE_CHANGE = "key_main_page_change"
+
+const val NO_SERVICE_ID = -1