[Password Manager] Add UMA stats for custom passphrase users.

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 2c49288d85942c13421fbd4db10c2c31191eb3ed..8d5ce2801841537a025618ebe49ff7463706b340 100644
--- a/components/password_manager/core/browser/password_manager_client.h
+++ b/components/password_manager/core/browser/password_manager_client.h
@@ -19,6 +19,11 @@ class PasswordFormManager;
 class PasswordManagerDriver;
 class PasswordStore;
 
+enum CustomPassphraseState {
+  EXCLUDE_CUSTOM_PASSPHRASE_USERS,

[vabr (Chromium), 2014/10/13 09:24:18]

What about renaming those to "WITHOUT_CUSTOM_PASSPHRASE" and
"WITH_CUSTOM_PASSPHRASE"?

Just from reading the code, I struggle to understand
"IsPasswordSyncEnabled(ONLY_CUSTOM_PASSPHRASE_USERS)" -- there is only one user
in the context. Whereas "IsPasswordSyncEnabled(WITH_CUSTOM_PASSPHRASE)" seems to
be exactly the question answered by the call, if I understand the implementation
correctly.

[Garrett Casto, 2014/10/13 20:57:56]

WITH_CUSTOM_PASSPHRASE sounds like it's inclusive (normal + custom passphrase)
which isn't right. Dropping _USERS seems reasonable, so I can imagine either
EXCLUDE_CUSTOM_PASSPHRASE and ONLY_CUSTOM_PASSPHRASE or
WITHOUT_CUSTOM_PASSPHRASE and ONLY_CUSTOM_PASSPHRASE. Preference?

[vabr (Chromium), 2014/10/14 07:32:51]

Good point with WITH_CUSTOM_PASSPHRASE sounding like it's inclusive.
From the two suggestions you made I prefer WITHOUT_CUSTOM_PASSPHRASE and
ONLY_CUSTOM_PASSPHRASE, simply because
IsPasswordSyncEnabled(WITHOUT_CUSTOM_PASSPHRASE) reads more naturally than
IsPasswordSyncEnabled(EXCLUDE_CUSTOM_PASSPHRASE). But both are acceptable to me.

+  ONLY_CUSTOM_PASSPHRASE_USERS
+};
+
 // An abstraction of operations that depend on the embedders (e.g. Chrome)
 // environment.
 class PasswordManagerClient {
@@ -40,6 +45,10 @@ class PasswordManagerClient {
   virtual bool ShouldFilterAutofillResult(
       const autofill::PasswordForm& form) = 0;
 
+  // Return the username that the user is syncing with. Should return an empty
+  // string if sync is not enabled for passwords.
+  virtual std::string GetSyncUsername() const = 0;
+
   // Returns true if |username| and |origin| correspond to the account which is
   // syncing.
   virtual bool IsSyncAccountCredential(
@@ -94,9 +103,10 @@ class PasswordManagerClient {
   virtual base::FieldTrial::Probability GetProbabilityForExperiment(
       const std::string& experiment_name);
 
-  // Returns true if password sync is enabled in the embedder. The default
-  // implementation returns false.
-  virtual bool IsPasswordSyncEnabled();
+  // Returns true if password sync is enabled in the embedder. Return value for
+  // custom passphrase users depends on |state|. The default implementation
+  // always returns false.
+  virtual bool IsPasswordSyncEnabled(CustomPassphraseState state);
 
   // Only for clients which registered with a LogRouter: If called with
   // |router_can_be_used| set to false, the client may no longer use the