Fix flaky BrowsingDataTest

Sometimes BrowsingDataTest.testCookiesDeleted fails because it gets a
result that doesn't contain number.
This can happen if the BrowsingDataCounter result isn't calculated
within 140ms and the counter responds with "Calculating...".
To fix test flakiness, we have to ignore these messages.

Bug: 909690
Change-Id: I087280bd98b8e5604a352692e3f0740e30eb4f02
Reviewed-on: https://chromium-review.googlesource.com/c/1353923
Commit-Queue: Christian Dullweber <dullweber@chromium.org>
Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611706}

chrome/android/javatests/src/org/chromium/chrome/browser/preferences/privacy/BrowsingDataTest.java

@@ -67,6 +67,7 @@ public class BrowsingDataTest {
         BrowsingDataCounterBridge[] counter = {null};
         CallbackHelper helper = new CallbackHelper();
         BrowsingDataCounterBridge.BrowsingDataCounterCallback callback = (result) -> {
+            if (result.equals("Calculating...")) return;
             out[0] = result;
             helper.notifyCalled();
         };
@@ -77,7 +78,9 @@ public class BrowsingDataTest {
         helper.waitForCallback(0);
         // The counter returns a result like "3 sites" or "None".
         if (out[0].equals("None")) return 0;
-        return Integer.parseInt(out[0].replaceAll("[^0-9]", ""));
+        String cookieCount = out[0].replaceAll("[^0-9]", "");
+        Assert.assertFalse("Result should contain a number: " + out[0], cookieCount.isEmpty());
+        return Integer.parseInt(cookieCount);
     }
 
     private String runJavascriptAsync(String type) throws Exception {