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

components/password_manager/core/browser/password_manager.cc

Index: components/password_manager/core/browser/password_manager.cc
diff --git a/components/password_manager/core/browser/password_manager.cc b/components/password_manager/core/browser/password_manager.cc
index dbd57f0b64da98d4bd8b6c7f12a993151ae9d274..a9b95a430ede672f89d5aa071d7576fc62696dd6 100644
--- a/components/password_manager/core/browser/password_manager.cc
+++ b/components/password_manager/core/browser/password_manager.cc
@@ -20,6 +20,7 @@
 #include "components/password_manager/core/common/password_manager_pref_names.h"
 #include "components/password_manager/core/common/password_manager_switches.h"
 #include "components/pref_registry/pref_registry_syncable.h"
+#include "net/base/registry_controlled_domains/registry_controlled_domain.h"
 
 #if defined(OS_WIN)
 #include "base/prefs/pref_registry_simple.h"
@@ -97,6 +98,16 @@ bool URLsEqualUpToHttpHttpsSubstitution(const GURL& a, const GURL& b) {
   return false;
 }
 
+// Helper UMA reporting function for differences in URLs during form submission.
+void RecordWhetherTargetDomainDiffers(const GURL& src, const GURL& target) {
+  bool target_domain_differs =
+      !net::registry_controlled_domains::SameDomainOrHost(
+          src, target,
+          net::registry_controlled_domains::INCLUDE_PRIVATE_REGISTRIES);
+  UMA_HISTOGRAM_BOOLEAN("PasswordManager.SubmitNavigatesToDifferentDomain",
+                        target_domain_differs);
+}
+
 }  // namespace
 
 const char PasswordManager::kOtherPossibleUsernamesExperiment[] =
@@ -309,6 +320,11 @@ void PasswordManager::ProvisionallySavePassword(const PasswordForm& form) {
   }
   manager->ProvisionallySave(provisionally_saved_form, action);
   provisional_save_manager_.swap(manager);
+
+  // Cache the user-visible URL (i.e., the one seen in the omnibox). Once the
+  // post-submit navigation concludes, we compare the landing URL against the
+  // cached and report the difference through UMA.
+  main_frame_url_ = client_->GetMainFrameURL();
 }
 
 void PasswordManager::RecordFailure(ProvisionalSaveFailure failure,
@@ -574,6 +590,8 @@ void PasswordManager::AskUserOrSavePassword() {
   }
   provisional_save_manager_->SubmitPassed();
 
+  RecordWhetherTargetDomainDiffers(main_frame_url_, client_->GetMainFrameURL());
+
   if (ShouldPromptUserToSavePassword()) {
     if (logger)
       logger->LogMessage(Logger::STRING_DECISION_ASK);