fix(Android): Workaround for chromium bugs 1023678 and 1050635.

There is a bug in the WebView that causes a spurious call to onReceivedError
whenever you download a file.

This commit is a workaround for that bug. The idea here is to try and detect
these spurious errors and drop them before they cause problems.

This commit should be reverted once those chromium bugs are fixed.

android/src/main/java/com/reactnativecommunity/webview/RNCWebViewManager.java

 
     webView.setDownloadListener(new DownloadListener() {
       public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype, long contentLength) {
+        webView.setIgnoreErrFailedForThisURL(url);
+
         RNCWebViewModule module = getModule(reactContext);
 
         DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));
     protected boolean mLastLoadFailed = false;
     protected @Nullable
     ReadableArray mUrlPrefixesForDefaultIntent;
+    protected @Nullable String ignoreErrFailedForThisURL = null;
+
+    public void setIgnoreErrFailedForThisURL(@Nullable String url) {
+      ignoreErrFailedForThisURL = url;
+    }
 
     @Override
     public void onPageFinished(WebView webView, String url) {
       int errorCode,
       String description,
       String failingUrl) {
+
+      if (ignoreErrFailedForThisURL != null
+          && failingUrl.equals(ignoreErrFailedForThisURL)
+          && errorCode == -1
+          && description.equals("net::ERR_FAILED")) {
+
+        // This is a workaround for a bug in the WebView.
+        // See these chromium issues for more context:
+        // https://bugs.chromium.org/p/chromium/issues/detail?id=1023678
+        // https://bugs.chromium.org/p/chromium/issues/detail?id=1050635
+        // This entire commit should be reverted once this bug is resolved in chromium.
+        setIgnoreErrFailedForThisURL(null);
+        return;
+      }
+
       super.onReceivedError(webView, errorCode, description, failingUrl);
       mLastLoadFailed = true;
 
       super(reactContext);
     }
 
+    public void setIgnoreErrFailedForThisURL(String url) {
+      mRNCWebViewClient.setIgnoreErrFailedForThisURL(url);
+    }
+
     public void setSendContentSizeChangeEvents(boolean sendContentSizeChangeEvents) {
       this.sendContentSizeChangeEvents = sendContentSizeChangeEvents;
     }