Lint fixes, change nullable annotation in preference manager

app/src/main/java/acr/browser/lightning/activity/BrowserActivity.java

@@ -559,8 +559,7 @@ public abstract class BrowserActivity extends ThemableBrowserActivity implements
         colorMode &= !mDarkTheme;
         if (!isIncognito() && !colorMode && !mDarkTheme && mWebpageBitmap != null) {
             changeToolbarBackground(mWebpageBitmap, null);
-        } else if (!isIncognito() && currentView != null && !mDarkTheme
-                && currentView.getFavicon() != null) {
+        } else if (!isIncognito() && currentView != null && !mDarkTheme) {
             changeToolbarBackground(currentView.getFavicon(), null);
         }
 

app/src/main/java/acr/browser/lightning/preference/PreferenceManager.java

@@ -391,7 +391,7 @@ public class PreferenceManager {
         putBoolean(Name.RESTORE_LOST_TABS, enable);
     }
 
-    public void setSavedUrl(@NonNull String url) {
+    public void setSavedUrl(@Nullable String url) {
         putString(Name.SAVE_URL, url);
     }