Fix sizing issues in the tab modal signin flow.

chrome/browser/ui/webui/signin/sync_confirmation_handler.cc

Index: chrome/browser/ui/webui/signin/sync_confirmation_handler.cc
diff --git a/chrome/browser/ui/webui/signin/sync_confirmation_handler.cc b/chrome/browser/ui/webui/signin/sync_confirmation_handler.cc
index df51a0d195a06e803804e9a1cb407d2a7358a3e3..5a65f9bf0620a5511213b91af3cfdf041b1ed88d 100644
--- a/chrome/browser/ui/webui/signin/sync_confirmation_handler.cc
+++ b/chrome/browser/ui/webui/signin/sync_confirmation_handler.cc
@@ -10,6 +10,7 @@
 #include "chrome/browser/signin/signin_manager_factory.h"
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/ui/browser_window.h"
+#include "chrome/browser/ui/signin_view_controller_delegate.h"
 #include "chrome/browser/ui/webui/signin/login_ui_service_factory.h"
 #include "components/signin/core/browser/account_tracker_service.h"
 #include "content/public/browser/user_metrics.h"
@@ -38,6 +39,9 @@ void SyncConfirmationHandler::RegisterMessages() {
   web_ui()->RegisterMessageCallback("goToSettings",
       base::Bind(&SyncConfirmationHandler::HandleGoToSettings,
                  base::Unretained(this)));
+  web_ui()->RegisterMessageCallback("resizeNativeView",
+      base::Bind(&SyncConfirmationHandler::HandleResizeNativeView,
+                 base::Unretained(this)));
 }
 
 void SyncConfirmationHandler::HandleConfirm(const base::ListValue* args) {
@@ -111,3 +115,16 @@ void SyncConfirmationHandler::CloseModalSigninWindow(
       SyncConfirmationUIClosed(results);
   browser->CloseModalSigninWindow();
 }
+
+void SyncConfirmationHandler::HandleResizeNativeView(
+    const base::ListValue* args) {
+  double height;
+  bool success = args->GetDouble(0, &height);
+  DCHECK(success);
+
+  Browser* browser = GetDesktopBrowser();
+  DCHECK(browser);
+
+  browser->signin_view_controller()->delegate()->ResizeNativeView(
+      static_cast<int>(height));
+}