Closes #2805 - review: Replace maybeGoBackBeforeFxaSignIn with crash …

…on gecko.

From Severin:
> I would replace this with a crash. If we ever move to GV, we'll want
> to know about this sooner rather than later. We can always comment it
> out at that time if it's considered low priority.

app/src/gecko/java/org/mozilla/tv/firefox/ext/EngineView.kt

@@ -10,7 +10,6 @@ import android.webkit.ValueCallback
 import android.widget.FrameLayout
 import androidx.annotation.VisibleForTesting
 import mozilla.components.concept.engine.EngineView
-import mozilla.components.support.base.log.logger.Logger
 import org.mozilla.geckoview.GeckoView
 import org.mozilla.geckoview.ScreenLength
 import org.mozilla.tv.firefox.ext.Js.CACHE_JS
@@ -24,8 +23,6 @@ import java.util.WeakHashMap
 // Extension methods on the EngineView class. This is used for additional features that are not part
 // of the upstream browser-engine(-gecko) component yet.
 
-private val logger = Logger("GeckoEngineView")
-
 private val uiHandler = Handler(Looper.getMainLooper())
 
 /**
@@ -181,7 +178,7 @@ val EngineView.backForwardList: WebHistory
     get() = WebHistory
 
 fun EngineView.maybeGoBackBeforeFxaSignIn() {
-    logger.warn("maybeGoBackBeforeFxaSignIn not implemented")
+    TODO("implemented only with system WebView to speed up development")
 }
 
 val EngineView.focusedDOMElement: FocusedDOMElementCache