[sync] Significantly speed up password model association on mac

chrome/browser/password_manager/password_store_mac_internal.h

Index: chrome/browser/password_manager/password_store_mac_internal.h
diff --git a/chrome/browser/password_manager/password_store_mac_internal.h b/chrome/browser/password_manager/password_store_mac_internal.h
index b7a2be49fca5dc1a7871226addcef97f36ee4821..ebaa24dea9e0c22fab611167d20475f2e4459041 100644
--- a/chrome/browser/password_manager/password_store_mac_internal.h
+++ b/chrome/browser/password_manager/password_store_mac_internal.h
@@ -49,6 +49,10 @@ class MacKeychainPasswordFormAdapter {
       const content::PasswordForm& query_form);
 
   // Returns all keychain items of types corresponding to password forms.
+  std::vector<SecKeychainItemRef> GetAllPasswordFormKeychainItems();
+
+  // Returns password data from all keychain items of types corresponding to
+  // password forms. Caller is responsible for deleting the returned forms.
   std::vector<content::PasswordForm*> GetAllPasswordFormPasswords();
 
   // Creates a new keychain entry from |form|, or updates the password of an
@@ -129,19 +133,23 @@ class MacKeychainPasswordFormAdapter {
 namespace internal_keychain_helpers {
 
 // Sets the fields of |form| based on the keychain data from |keychain_item|.
-// Fields that can't be determined from |keychain_item| will be unchanged.
+// Fields that can't be determined from |keychain_item| will be unchanged. If
+// |extract_password_data| is true, the password data will be copied from
+// |keychain_item| in addition to its attributes. If it is false, only the
+// password attributes will be copied.
 //
-// IMPORTANT: This function can cause the OS to trigger UI (to allow access to
-// the keychain item if we aren't trusted for the item), and block until the UI
-// is dismissed.
+// IMPORTANT: If |extract_password_data| is true, this function can cause the OS
+// to trigger UI (to allow access to the keychain item if we aren't trusted for
+// the item), and block until the UI is dismissed.
 //
 // If excessive prompting for access to other applications' keychain items
-// becomes an issue, the password storage API will need to be refactored to
-// allow the password to be retrieved later (accessing other fields doesn't
-// require authorization).
+// becomes an issue, the password storage API will need to intially call this
+// function with |extract_password_data| set to false, and retrieve the password
+// later (accessing other fields doesn't require authorization).
 bool FillPasswordFormFromKeychainItem(const AppleKeychain& keychain,
                                       const SecKeychainItemRef& keychain_item,
-                                      content::PasswordForm* form);
+                                      content::PasswordForm* form,
+                                      bool extract_password_data);
 
 // Returns true if the two given forms match based on signon_reaml, scheme, and
 // username_value, and are thus suitable for merging (see MergePasswordForms).