Use standardized accelerator-to-shortcut code for new backspace shortcut UI.

chrome/browser/ui/browser_command_controller.cc

Index: chrome/browser/ui/browser_command_controller.cc
diff --git a/chrome/browser/ui/browser_command_controller.cc b/chrome/browser/ui/browser_command_controller.cc
index 33b18439dd190874d5c2f4000f7494c10f6a6b3b..3a3e0a58f841033d110c91254dbe0f07d9df3000 100644
--- a/chrome/browser/ui/browser_command_controller.cc
+++ b/chrome/browser/ui/browser_command_controller.cc
@@ -305,7 +305,7 @@ void BrowserCommandController::ExecuteCommandWithDisposition(
       if (base::FeatureList::IsEnabled(features::kBackspaceGoesBackFeature))
         GoBack(browser_, disposition);
       else
-        browser_->window()->MaybeShowNewBackShortcutBubble(false);
+        browser_->window()->MaybeShowNewBackShortcutBubble(IDC_BACK);
       break;
     case IDC_BACK:
       browser_->window()->HideNewBackShortcutBubble();
@@ -315,7 +315,7 @@ void BrowserCommandController::ExecuteCommandWithDisposition(
       if (base::FeatureList::IsEnabled(features::kBackspaceGoesBackFeature))
         GoForward(browser_, disposition);
       else
-        browser_->window()->MaybeShowNewBackShortcutBubble(true);
+        browser_->window()->MaybeShowNewBackShortcutBubble(IDC_FORWARD);
       break;
     case IDC_FORWARD:
       browser_->window()->HideNewBackShortcutBubble();