[Password Manager] Add UMA signals to understand how often the password form submit navigate…

components/password_manager/core/browser/password_manager_client.h

Index: components/password_manager/core/browser/password_manager_client.h
diff --git a/components/password_manager/core/browser/password_manager_client.h b/components/password_manager/core/browser/password_manager_client.h
index c068bb14cdbc71060479e95b3c18bd284b408407..2b791a7288fc6f85c9b694685961e0527e74d74d 100644
--- a/components/password_manager/core/browser/password_manager_client.h
+++ b/components/password_manager/core/browser/password_manager_client.h
@@ -160,6 +160,9 @@ class PasswordManagerClient {
   // Returns the AutofillManager for the main frame.
   virtual autofill::AutofillManager* GetAutofillManagerForMainFrame();
 
+  // Returns the main frame URL.
+  virtual const GURL& GetMainFrameURL();
+
  private:
   DISALLOW_COPY_AND_ASSIGN(PasswordManagerClient);
 };