Don't call SpinnerLogger.spinnerFinished() if spinner isn't shown

Just prevents reaching the Logger.wtf(). Considering a refactoring of
the Feed library is soon to be underway, there's not much point in
investigating why the spinner isn't being shown in the first place.

Bug: 992570
Change-Id: I693bd57bb60e5396f565a3b8fd8bb2c3cc08d1e2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2006423
Commit-Queue: Ian Wells <iwells@chromium.org>
Commit-Queue: Dan H <harringtond@chromium.org>
Auto-Submit: Ian Wells <iwells@chromium.org>
Reviewed-by: Dan H <harringtond@chromium.org>
Cr-Commit-Position: refs/heads/master@{#732912}

chrome/android/feed/core/java/src/org/chromium/chrome/browser/feed/library/basicstream/internal/drivers/ContinuationDriver.java

@@ -232,7 +232,9 @@ public class ContinuationDriver extends LeafFeatureDriver
     public void onError(ModelError modelError) {
         mBasicLoggingApi.onTokenFailedToComplete(mModelToken.isSynthetic(), ++mFailureCount);
         showErrorUi();
-        mSpinnerLogger.spinnerFinished();
+        if (mSpinnerLogger.isSpinnerActive()) {
+            mSpinnerLogger.spinnerFinished();
+        }
     }
 
     private void showErrorUi() {