Add "PasswordManager.SignInPromoDismissalCount" histogram.

chrome/browser/ui/passwords/manage_passwords_bubble_model.cc

Index: chrome/browser/ui/passwords/manage_passwords_bubble_model.cc
diff --git a/chrome/browser/ui/passwords/manage_passwords_bubble_model.cc b/chrome/browser/ui/passwords/manage_passwords_bubble_model.cc
index 5fd990e74cb4e13c306cc8af337a66862a2ea0d0..bfdeb0085961f31877ed86ee437b0c4239acfc1a 100644
--- a/chrome/browser/ui/passwords/manage_passwords_bubble_model.cc
+++ b/chrome/browser/ui/passwords/manage_passwords_bubble_model.cc
@@ -103,6 +103,10 @@ class ManagePasswordsBubbleModel::InteractionKeeper {
     clock_ = std::move(clock);
   }
 
+  void set_sign_in_promo_count(int count) {
+    sign_in_promo_count = count;
+  }
+
  private:
   // The way the bubble appeared.
   const password_manager::metrics_util::UIDisplayDisposition
@@ -125,6 +129,9 @@ class ManagePasswordsBubbleModel::InteractionKeeper {
   // Used to retrieve the current time, in base::Time units.
   std::unique_ptr<base::Clock> clock_;
 
+  // Number of times the sign-in promo was shown to the user.
+  int sign_in_promo_count;

[Ilya Sherman, 2016/11/05 01:31:39]

nit: I'd add "shown" before "count"

[vasilii, 2016/11/07 10:40:24]

Done.

+
   DISALLOW_COPY_AND_ASSIGN(InteractionKeeper);
 };
 
@@ -136,7 +143,8 @@ ManagePasswordsBubbleModel::InteractionKeeper::InteractionKeeper(
       update_password_submission_event_(metrics_util::NO_UPDATE_SUBMISSION),
       sign_in_promo_dismissal_reason_(metrics_util::CHROME_SIGNIN_DISMISSED),
       interaction_stats_(std::move(stats)),
-      clock_(new base::DefaultClock) {}
+      clock_(new base::DefaultClock),
+      sign_in_promo_count(0) {}
 
 void ManagePasswordsBubbleModel::InteractionKeeper::ReportInteractions(
     const ManagePasswordsBubbleModel* model) {
@@ -170,11 +178,11 @@ void ManagePasswordsBubbleModel::InteractionKeeper::ReportInteractions(
             password_manager::metrics_util::CHROME_SIGNIN_OK ||
         sign_in_promo_dismissal_reason_ ==
             password_manager::metrics_util::CHROME_SIGNIN_CANCEL) {
-      DCHECK(model->delegate_);
-      int show_count = model->GetProfile()->GetPrefs()->GetInteger(
-          password_manager::prefs::kNumberSignInPasswordPromoShown);
       UMA_HISTOGRAM_COUNTS_100("PasswordManager.SignInPromoCountTilClick",
-                               show_count);
+                               sign_in_promo_count);
+    } else {
+      UMA_HISTOGRAM_COUNTS_100("PasswordManager.SignInPromoDismissalCount",

[Ilya Sherman, 2016/11/05 01:31:40]

Does CHROME_SIGNIN_CANCEL not correspond to a dismissal?

[vasilii, 2016/11/07 10:40:24]

No. The request was to count implicit dismissals. CHROME_SIGNIN_CANCEL and
CHROME_SIGNIN_OK both contribute to click-through rate. The dialog won't show up
again.

+                               sign_in_promo_count);
     }
   } else if (model->state() !=
              password_manager::ui::PENDING_PASSWORD_UPDATE_STATE) {
@@ -446,8 +454,10 @@ bool ManagePasswordsBubbleModel::ReplaceToShowSignInPromoIfNeeded() {
     state_ = password_manager::ui::CHROME_SIGN_IN_PROMO_STATE;
     int show_count = prefs->GetInteger(
         password_manager::prefs::kNumberSignInPasswordPromoShown);
+    show_count++;

[Ilya Sherman, 2016/11/05 01:31:39]

nit: Please use pre-increment.

[vasilii, 2016/11/07 10:40:24]

Why?

[Ilya Sherman, 2016/11/07 19:43:20]

Hmm, I think the style guide used to recommend pre-incrmenet universally.  I
guess that's not the case anymore, so nevermind.

[vabr (Chromium), 2016/11/08 08:36:33]

The style guide still requires it for iterators, but explicitly says it does not
matter for non-object values:
https://google.github.io/styleguide/cppguide.html#Preincrement_and_Predecrement

     prefs->SetInteger(password_manager::prefs::kNumberSignInPasswordPromoShown,
-                      show_count + 1);
+                      show_count);
+    interaction_keeper_->set_sign_in_promo_count(show_count);

[Ilya Sherman, 2016/11/05 01:31:39]

What's the purpose of tracking this in two locations?  That is, why not just
track it exclusively via the pref that's being set above?

[vasilii, 2016/11/07 10:40:24]

Because if one closes the tab then GetWebContents() returns 0.
PasswordsModelDelegate may also be null. Their destruction order can't be
predicted. I can't find a profile then.

     return true;
   }
   return false;