Fill is_chrome_signin_password field in the password entry pings.

components/password_manager/core/browser/password_reuse_detector.h

Index: components/password_manager/core/browser/password_reuse_detector.h
diff --git a/components/password_manager/core/browser/password_reuse_detector.h b/components/password_manager/core/browser/password_reuse_detector.h
index 3cf65696bdb04904fc6ca0d977ba28c20950612b..f6d2d49d66ada9fca033c4562c9e9927c446e1b1 100644
--- a/components/password_manager/core/browser/password_reuse_detector.h
+++ b/components/password_manager/core/browser/password_reuse_detector.h
@@ -29,6 +29,9 @@ struct ReverseStringLess {
   bool operator()(const base::string16& lhs, const base::string16& rhs) const;
 };
 
+// Used to identify chrome sync password in password entry event.
+extern const char kSyncPasswordDomain[];
+
 // Per-profile class responsible for detection of password reuse, i.e. that the
 // user input on some site contains the password saved on another site.
 // It receives saved passwords through PasswordStoreConsumer interface.