Convert webview into an activity (#2470)

Based on https://github.com/Jays2Kings/tachiyomiJ2K/commit/65804ebb3aca0a79377167334ff842c0789440f3

app/src/main/java/eu/kanade/tachiyomi/ui/base/activity/BaseActivity.kt

@@ -1,13 +1,29 @@
 package eu.kanade.tachiyomi.ui.base.activity
 
+import android.os.Bundle
 import androidx.appcompat.app.AppCompatActivity
+import eu.kanade.tachiyomi.R
+import eu.kanade.tachiyomi.data.preference.PreferencesHelper
 import eu.kanade.tachiyomi.util.LocaleHelper
+import uy.kohesive.injekt.injectLazy
 
 abstract class BaseActivity : AppCompatActivity() {
 
+    val preferences: PreferencesHelper by injectLazy()
+
     init {
         @Suppress("LeakingThis")
         LocaleHelper.updateConfiguration(this)
     }
 
+    override fun onCreate(savedInstanceState: Bundle?) {
+        setTheme(when (preferences.theme()) {
+            2 -> R.style.Theme_Tachiyomi_Dark
+            3 -> R.style.Theme_Tachiyomi_Amoled
+            4 -> R.style.Theme_Tachiyomi_DarkBlue
+            else -> R.style.Theme_Tachiyomi
+        })
+        super.onCreate(savedInstanceState)
+    }
+
 }