[Extension UI Views] Add tests for clicking the different message bubble buttons

chrome/browser/ui/views/extensions/extension_message_bubble_view.cc

Index: chrome/browser/ui/views/extensions/extension_message_bubble_view.cc
diff --git a/chrome/browser/ui/views/extensions/extension_message_bubble_view.cc b/chrome/browser/ui/views/extensions/extension_message_bubble_view.cc
index 5b2f92016bf446f180f419b3a157a7737888156b..a3c156dd3fe94adcb845627c67b907d0659dff63 100644
--- a/chrome/browser/ui/views/extensions/extension_message_bubble_view.cc
+++ b/chrome/browser/ui/views/extensions/extension_message_bubble_view.cc
@@ -40,6 +40,9 @@ int g_bubble_appearance_wait_time = 5;
 
 namespace extensions {
 
+ExtensionMessageBubbleView*
+    ExtensionMessageBubbleView::active_bubble_for_testing_ = nullptr;
+
 ExtensionMessageBubbleView::ExtensionMessageBubbleView(
     views::View* anchor_view,
     views::BubbleBorder::Arrow arrow_location,
@@ -77,6 +80,8 @@ void ExtensionMessageBubbleView::Show() {
 }
 
 void ExtensionMessageBubbleView::OnWidgetDestroying(views::Widget* widget) {
+  if (active_bubble_for_testing_ == this)
+    active_bubble_for_testing_ = nullptr;
   // To catch Esc, we monitor destroy message. Unless the link has been clicked,
   // we assume Dismiss was the action taken.
   if (!link_clicked_ && !action_taken_) {
@@ -96,6 +101,7 @@ void ExtensionMessageBubbleView::set_bubble_appearance_wait_time_for_testing(
 ExtensionMessageBubbleView::~ExtensionMessageBubbleView() {}
 
 void ExtensionMessageBubbleView::ShowBubble() {
+  active_bubble_for_testing_ = this;
   // Since we delay in showing the bubble, the applicable extension(s) may
   // have been removed.
   if (controller_->ShouldShow()) {