Added |lastCommittedURL| and |visibleURL| to Tab's interface.

ios/chrome/browser/tabs/tab.h

Index: ios/chrome/browser/tabs/tab.h
diff --git a/ios/chrome/browser/tabs/tab.h b/ios/chrome/browser/tabs/tab.h
index 8c87b0266fa35edbb24b316e459b90fb22bbf297..bd4b5aaecba0efb0a2a3e0ca1ee74121056270c8 100644
--- a/ios/chrome/browser/tabs/tab.h
+++ b/ios/chrome/browser/tabs/tab.h
@@ -106,6 +106,12 @@ extern NSString* const kProxyPassthroughHeaderValue;
 // Do not add new calls to this method.
 @property(nonatomic, readonly) const GURL& url;
 
+// Returns the URL of the last committed NavigationItem for this Tab.
+@property(nonatomic, readonly) const GURL& lastCommittedURL;
+
+// Returns the URL of the visible NavigationItem for this Tab.
+@property(nonatomic, readonly) const GURL& visibleURL;
+
 // The Passkit Dialog provider used to show the UI to download a passkit object.
 @property(nonatomic, assign) id<PassKitDialogProvider> passKitDialogProvider;