Using UrlConstants instead of hardcoded values in few places

chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchManager.java

Index: chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchManager.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchManager.java b/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchManager.java
index b1326829259d5fa61a1d710025013dcdebf2d342..5efc8793275151000e48b6084e5862fce6d2e5ab 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchManager.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/contextualsearch/ContextualSearchManager.java
@@ -17,6 +17,7 @@ import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.metrics.RecordUserAction;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.ChromeActivity;
+import org.chromium.chrome.browser.UrlConstants;
 import org.chromium.chrome.browser.compositor.bottombar.OverlayContentDelegate;
 import org.chromium.chrome.browser.compositor.bottombar.OverlayPanel.PanelState;
 import org.chromium.chrome.browser.compositor.bottombar.OverlayPanel.StateChangeReason;
@@ -75,7 +76,7 @@ public class ContextualSearchManager implements ContextualSearchManagementDelega
     private static final long INTERCEPT_NAVIGATION_PROMOTION_ANIMATION_DURATION_MS = 40;
 
     // We blacklist this URL because malformed URLs may bring up this page.
-    private static final String BLACKLISTED_URL = "about:blank";
+    private static final String BLACKLISTED_URL = UrlConstants.ABOUT_BLANK_DISPLAY_URL;
 
     private static final Pattern CONTAINS_WHITESPACE_PATTERN = Pattern.compile("\\s");