Added notification when user presses backspace to use new shortcut.

chrome/browser/ui/views/frame/browser_view.cc

Index: chrome/browser/ui/views/frame/browser_view.cc
diff --git a/chrome/browser/ui/views/frame/browser_view.cc b/chrome/browser/ui/views/frame/browser_view.cc
index 5be5b95280c0da1d5cc8d380374d1497212aa71b..32f49a7d8e05b98945e1a8b05dbf64b67f2b9775 100644
--- a/chrome/browser/ui/views/frame/browser_view.cc
+++ b/chrome/browser/ui/views/frame/browser_view.cc
@@ -82,6 +82,7 @@
 #include "chrome/browser/ui/views/location_bar/location_bar_view.h"
 #include "chrome/browser/ui/views/location_bar/location_icon_view.h"
 #include "chrome/browser/ui/views/location_bar/zoom_bubble_view.h"
+#include "chrome/browser/ui/views/new_back_shortcut_bubble.h"
 #include "chrome/browser/ui/views/omnibox/omnibox_view_views.h"
 #include "chrome/browser/ui/views/profiles/avatar_menu_button.h"
 #include "chrome/browser/ui/views/profiles/profile_chooser_view.h"
@@ -978,7 +979,13 @@ void BrowserView::UpdateExclusiveAccessExitBubbleContent(
   if (bubble_type == EXCLUSIVE_ACCESS_BUBBLE_TYPE_NONE ||
       ShouldUseImmersiveFullscreenForUrl(url)) {
     exclusive_access_bubble_.reset();
-  } else if (exclusive_access_bubble_.get()) {
+    return;
+  }
+
+  // Hide the backspace shortcut bubble, to avoid overlapping.
+  new_back_shortcut_bubble_.reset();
+
+  if (exclusive_access_bubble_) {
     exclusive_access_bubble_->UpdateContent(url, bubble_type);
   } else {
     exclusive_access_bubble_.reset(
@@ -1007,6 +1014,16 @@ bool BrowserView::IsFullscreenBubbleVisible() const {
   return exclusive_access_bubble_ != nullptr;
 }
 
+void BrowserView::ShowNewBackShortcutBubble(bool forward) {
+  // Hide the exclusive access bubble, to avoid overlapping.
+  exclusive_access_bubble_.reset();
+
+  if (new_back_shortcut_bubble_)
+    new_back_shortcut_bubble_->UpdateContent(forward);
+  else
+    new_back_shortcut_bubble_.reset(new NewBackShortcutBubble(this, forward));
+}
+
 void BrowserView::RestoreFocus() {
   WebContents* selected_web_contents = GetActiveWebContents();
   if (selected_web_contents)