Add debug logging to WebApk network errors.

Touchless tests are hitting network errors inexplicably on bots, and I'm
unable to repro locally, so I'm adding logging to hopefully get more
insight.

Bug: 983769
Change-Id: If9ed3b7569c1d26a7923bac5f458a44fb4edb331
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1741291Reviewed-by: Peter Kotwicz <pkotwicz@chromium.org>
Commit-Queue: Michael Thiessen <mthiesse@chromium.org>
Cr-Commit-Position: refs/heads/master@{#685195}

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkSplashNetworkErrorObserver.java

@@ -8,6 +8,7 @@ import android.app.Activity;
 import android.content.Context;
 
 import org.chromium.base.ContextUtils;
+import org.chromium.base.Log;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.metrics.WebApkUma;
 import org.chromium.chrome.browser.tab.EmptyTabObserver;
@@ -21,6 +22,7 @@ import org.chromium.net.NetworkChangeNotifier;
  * start URL.
  */
 public class WebApkSplashNetworkErrorObserver extends EmptyTabObserver {
+    private static final String TAG = "WebApkSplashNetObs";
     private Activity mActivity;
     private WebApkOfflineDialog mOfflineDialog;
     private String mWebApkName;
@@ -54,6 +56,11 @@ public class WebApkSplashNetworkErrorObserver extends EmptyTabObserver {
                 onNetworkChanged(tab);
                 break;
             default:
+                // TODO(mthiesse): These logs are for debugging https://crbug.com/983769 and should
+                // be removed once that's resolved.
+                Log.d(TAG,
+                        "Network error loading WebApk at URL: " + navigation.getUrl()
+                                + ", with error: " + navigation.errorCode());
                 onNetworkError(tab, navigation.errorCode());
                 break;
         }