GTK: button clicking cleanup.

I found a much better way to implement middle-click-to-navigate: use gtk_get_current_event() to get the button release event that triggered the "clicked" signal. This simplifies greatly a lot of places that I had previously added complication.

Also this adds middle click to navigate on the go button.
Also this makes middle click on a bookmark bar button depress the button.


Review URL: http://codereview.chromium.org/165261

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@22976 0039d316-1c4b-4281-b951-d872f2087c98

11 files changed, 34 insertions, 153 deletions

diff --git a/chrome/browser/gtk/back_forward_button_gtk.cc b/chrome/browser/gtk/back_forward_button_gtk.cc
index 009be74..7f4bd69 100644
--- a/chrome/browser/gtk/back_forward_button_gtk.cc
+++ b/chrome/browser/gtk/back_forward_button_gtk.cc
@@ -24,7 +24,6 @@ static const int kMenuTimerDelay = 500;
 BackForwardButtonGtk::BackForwardButtonGtk(Browser* browser, bool is_forward)
     : browser_(browser),
       is_forward_(is_forward),
-      last_release_event_flags_(0),
       show_menu_factory_(this) {
   int normal, active, highlight, depressed, tooltip;
   const char* stock;
@@ -59,8 +58,6 @@ BackForwardButtonGtk::BackForwardButtonGtk(Browser* browser, bool is_forward)
                    G_CALLBACK(OnClick), this);
   g_signal_connect(widget(), "button-press-event",
                    G_CALLBACK(OnButtonPress), this);
-  g_signal_connect(widget(), "button-release-event",
-                   G_CALLBACK(OnButtonRelease), this);
   gtk_widget_add_events(widget(), GDK_POINTER_MOTION_MASK);
   g_signal_connect(widget(), "motion-notify-event",
                    G_CALLBACK(OnMouseMove), this);
@@ -96,19 +93,17 @@ void BackForwardButtonGtk::ShowBackForwardMenu() {
 void BackForwardButtonGtk::OnClick(GtkWidget* widget,
                                    BackForwardButtonGtk* button) {
   button->show_menu_factory_.RevokeAll();
+  GdkEventButton* event =
+      reinterpret_cast<GdkEventButton*>(gtk_get_current_event());
 
-  DCHECK(button->last_release_event_flags_ != 0);
   button->browser_->ExecuteCommandWithDisposition(
       button->is_forward_ ? IDC_FORWARD : IDC_BACK,
-      event_utils::DispositionFromEventFlags(
-          button->last_release_event_flags_));
+      event_utils::DispositionFromEventFlags(event->state));
 }
 
 // static
 gboolean BackForwardButtonGtk::OnButtonPress(GtkWidget* widget,
     GdkEventButton* event, BackForwardButtonGtk* button) {
-  button->last_release_event_flags_ = 0;
-
   if (event->button == 3)
     button->ShowBackForwardMenu();
 
@@ -124,13 +119,6 @@ gboolean BackForwardButtonGtk::OnButtonPress(GtkWidget* widget,
 }
 
 // static
-gboolean BackForwardButtonGtk::OnButtonRelease(GtkWidget* widget,
-    GdkEventButton* event, BackForwardButtonGtk* button) {
-  button->last_release_event_flags_ = event->state;
-  return FALSE;
-}
-
-// static
 gboolean BackForwardButtonGtk::OnMouseMove(GtkWidget* widget,
     GdkEventMotion* event, BackForwardButtonGtk* button) {
   // If we aren't waiting to show the back forward menu, do nothing.
diff --git a/chrome/browser/gtk/back_forward_button_gtk.h b/chrome/browser/gtk/back_forward_button_gtk.h
index cb4c1ab..49ea05f 100644
--- a/chrome/browser/gtk/back_forward_button_gtk.h
+++ b/chrome/browser/gtk/back_forward_button_gtk.h
@@ -36,10 +36,6 @@ class BackForwardButtonGtk {
                                 GdkEventButton* event,
                                 BackForwardButtonGtk* toolbar);
 
-  static gboolean OnButtonRelease(GtkWidget* button,
-                                  GdkEventButton* event,
-                                  BackForwardButtonGtk* toolbar);
-
   // If there is a timer to show the dropdown menu, and the mouse has moved
   // sufficiently down the screen, cancel the timer and immediately show the
   // menu.
@@ -61,9 +57,6 @@ class BackForwardButtonGtk {
   // Whether this button is a forward button.
   bool is_forward_;
 
-  // The event state from the last button release.
-  int last_release_event_flags_;
-
   // The dropdown menu delegate.
   scoped_ptr<BackForwardMenuModelGtk> menu_model_;
 
diff --git a/chrome/browser/gtk/bookmark_bar_gtk.cc b/chrome/browser/gtk/bookmark_bar_gtk.cc
index b3f4e96..359a2bc 100644
--- a/chrome/browser/gtk/bookmark_bar_gtk.cc
+++ b/chrome/browser/gtk/bookmark_bar_gtk.cc
@@ -82,7 +82,6 @@ BookmarkBarGtk::BookmarkBarGtk(Profile* profile, Browser* browser,
       window_(window),
       model_(NULL),
       instructions_(NULL),
-      ignore_button_release_(false),
       dragged_node_(NULL),
       toolbar_drop_item_(NULL),
       theme_provider_(GtkThemeProvider::GetFrom(profile)),
@@ -437,8 +436,9 @@ GtkWidget* BookmarkBarGtk::CreateBookmarkButton(const BookmarkNode* node) {
     // button.
     g_signal_connect(G_OBJECT(button), "button-press-event",
                      G_CALLBACK(OnButtonPressed), this);
-    g_signal_connect(G_OBJECT(button), "button-release-event",
-                     G_CALLBACK(OnButtonReleased), this);
+    g_signal_connect(G_OBJECT(button), "clicked",
+                     G_CALLBACK(OnClicked), this);
+    gtk_util::SetButtonTriggersNavigation(button);
   } else {
     // TODO(erg): This button can also be a drop target.
     ConnectFolderButtonEvents(button);
@@ -470,8 +470,8 @@ void BookmarkBarGtk::ConnectFolderButtonEvents(GtkWidget* widget) {
   // button.
   g_signal_connect(G_OBJECT(widget), "button-press-event",
                    G_CALLBACK(OnButtonPressed), this);
-  g_signal_connect(G_OBJECT(widget), "button-release-event",
-                   G_CALLBACK(OnFolderButtonReleased), this);
+  g_signal_connect(G_OBJECT(widget), "clicked",
+                   G_CALLBACK(OnFolderClicked), this);
 }
 
 const BookmarkNode* BookmarkBarGtk::GetNodeForToolButton(GtkWidget* widget) {
@@ -534,10 +534,6 @@ void BookmarkBarGtk::PopupMenuForNode(GtkWidget* sender,
 gboolean BookmarkBarGtk::OnButtonPressed(GtkWidget* sender,
                                          GdkEventButton* event,
                                          BookmarkBarGtk* bar) {
-  if (sender != bar->other_bookmarks_button_ &&
-      sender != bar->bookmark_toolbar_.get())
-    bar->ignore_button_release_ = false;
-
   if (event->button == 3) {
     const BookmarkNode* node = bar->GetNodeForToolButton(sender);
     DCHECK(node);
@@ -549,25 +545,15 @@ gboolean BookmarkBarGtk::OnButtonPressed(GtkWidget* sender,
 }
 
 // static
-gboolean BookmarkBarGtk::OnButtonReleased(GtkWidget* sender,
-                                          GdkEventButton* event,
-                                          BookmarkBarGtk* bar) {
-  if (bar->ignore_button_release_) {
-    // Don't handle this message; it was a drag.
-    bar->ignore_button_release_ = false;
-    return FALSE;
-  }
-
-  // Don't take any action if the user releases outside the button.
-  if (event->x < 0 || event->y < 0 || event->x >= sender->allocation.width ||
-      event->y >= sender->allocation.height) {
-    return FALSE;
-  }
-
+void BookmarkBarGtk::OnClicked(GtkWidget* sender,
+                               BookmarkBarGtk* bar) {
   const BookmarkNode* node = bar->GetNodeForToolButton(sender);
   DCHECK(node);
   DCHECK(bar->page_navigator_);
 
+  GdkEventButton* event =
+      reinterpret_cast<GdkEventButton*>(gtk_get_current_event());
+
   if (node->is_url()) {
     bar->page_navigator_->OpenURL(
         node->GetURL(), GURL(),
@@ -580,9 +566,6 @@ gboolean BookmarkBarGtk::OnButtonReleased(GtkWidget* sender,
   }
 
   UserMetrics::RecordAction(L"ClickedBookmarkBarURLButton", bar->profile_);
-
-  // Allow other handlers to run so the button state is updated correctly.
-  return FALSE;
 }
 
 // static
@@ -593,10 +576,6 @@ void BookmarkBarGtk::OnButtonDragBegin(GtkWidget* button,
   // won't get destroyed.
   g_object_ref(button->parent);
 
-  // Signal to any future OnButtonReleased calls that we're dragging instead of
-  // pressing.
-  bar->ignore_button_release_ = true;
-
   const BookmarkNode* node = bar->GetNodeForToolButton(button);
   DCHECK(!bar->dragged_node_);
   bar->dragged_node_ = node;
@@ -640,15 +619,8 @@ void BookmarkBarGtk::OnButtonDragGet(GtkWidget* widget, GdkDragContext* context,
 }
 
 // static
-gboolean BookmarkBarGtk::OnFolderButtonReleased(GtkWidget* sender,
-                                                GdkEventButton* event,
-                                                BookmarkBarGtk* bar) {
-  if (bar->ignore_button_release_) {
-    // Don't handle this message; it was a drag.
-    bar->ignore_button_release_ = false;
-    return FALSE;
-  }
-
+void BookmarkBarGtk::OnFolderClicked(GtkWidget* sender,
+                                     BookmarkBarGtk* bar) {
   const BookmarkNode* node = bar->GetNodeForToolButton(sender);
   DCHECK(node);
   DCHECK(bar->page_navigator_);
@@ -660,10 +632,9 @@ gboolean BookmarkBarGtk::OnFolderButtonReleased(GtkWidget* sender,
                                  node,
                                  0,
                                  false));
+  GdkEventButton* event =
+      reinterpret_cast<GdkEventButton*>(gtk_get_current_event());
   bar->current_menu_->Popup(sender, event->button, event->time);
-
-  // Allow other handlers to run so the button state is updated correctly.
-  return FALSE;
 }
 
 // static
diff --git a/chrome/browser/gtk/bookmark_bar_gtk.h b/chrome/browser/gtk/bookmark_bar_gtk.h
index 6600046..3136527 100644
--- a/chrome/browser/gtk/bookmark_bar_gtk.h
+++ b/chrome/browser/gtk/bookmark_bar_gtk.h
@@ -142,9 +142,8 @@ class BookmarkBarGtk : public AnimationDelegate,
   static gboolean OnButtonPressed(GtkWidget* sender,
                                   GdkEventButton* event,
                                   BookmarkBarGtk* bar);
-  static gboolean OnButtonReleased(GtkWidget* sender,
-                                   GdkEventButton* event,
-                                   BookmarkBarGtk* bar);
+  static void OnClicked(GtkWidget* sender,
+                        BookmarkBarGtk* bar);
   static void OnButtonDragBegin(GtkWidget* widget,
                                 GdkDragContext* drag_context,
                                 BookmarkBarGtk* bar);
@@ -157,9 +156,8 @@ class BookmarkBarGtk : public AnimationDelegate,
                               BookmarkBarGtk* bar);
 
   // GtkButton callbacks for folder buttons.
-  static gboolean OnFolderButtonReleased(GtkWidget* sender,
-                                         GdkEventButton* event,
-                                         BookmarkBarGtk* bar);
+  static void OnFolderClicked(GtkWidget* sender,
+                              BookmarkBarGtk* bar);
 
   // GtkToolbar callbacks.
   static gboolean OnToolbarExpose(GtkWidget* widget, GdkEventExpose* event,
@@ -216,10 +214,6 @@ class BookmarkBarGtk : public AnimationDelegate,
   // The other bookmarks button.
   GtkWidget* other_bookmarks_button_;
 
-  // Whether we should ignore the next button release event (because we were
-  // dragging).
-  bool ignore_button_release_;
-
   // The BookmarkNode from the model being dragged. NULL when we aren't
   // dragging.
   const BookmarkNode* dragged_node_;
diff --git a/chrome/browser/gtk/browser_toolbar_gtk.cc b/chrome/browser/gtk/browser_toolbar_gtk.cc
index 1a3f83d..81ec816 100644
--- a/chrome/browser/gtk/browser_toolbar_gtk.cc
+++ b/chrome/browser/gtk/browser_toolbar_gtk.cc
@@ -78,8 +78,7 @@ BrowserToolbarGtk::BrowserToolbarGtk(Browser* browser, BrowserWindowGtk* window)
       model_(browser->toolbar_model()),
       browser_(browser),
       window_(window),
-      profile_(NULL),
-      last_release_event_flags_(0) {
+      profile_(NULL) {
   browser_->command_updater()->AddCommandObserver(IDC_BACK, this);
   browser_->command_updater()->AddCommandObserver(IDC_FORWARD, this);
   browser_->command_updater()->AddCommandObserver(IDC_RELOAD, this);
@@ -443,8 +442,6 @@ CustomDrawButton* BrowserToolbarGtk::BuildToolbarButton(
                               localized_tooltip.c_str());
   g_signal_connect(button->widget(), "clicked",
                    G_CALLBACK(OnButtonClick), this);
-  g_signal_connect(button->widget(), "button-release-event",
-                   G_CALLBACK(OnButtonRelease), this);
 
   gtk_box_pack_start(GTK_BOX(toolbar_), button->widget(), FALSE, FALSE, 0);
   return button;
@@ -626,15 +623,7 @@ void BrowserToolbarGtk::OnButtonClick(GtkWidget* button,
   DCHECK_NE(tag, -1) << "Unexpected button click callback";
   toolbar->browser_->ExecuteCommandWithDisposition(tag,
       event_utils::DispositionFromEventFlags(
-          toolbar->last_release_event_flags_));
-}
-
-// static
-gboolean BrowserToolbarGtk::OnButtonRelease(GtkWidget* button,
-                                            GdkEventButton* event,
-                                            BrowserToolbarGtk* toolbar) {
-  toolbar->last_release_event_flags_ = event->state;
-  return FALSE;
+      reinterpret_cast<GdkEventButton*>(gtk_get_current_event())->state));
 }
 
 // static
diff --git a/chrome/browser/gtk/browser_toolbar_gtk.h b/chrome/browser/gtk/browser_toolbar_gtk.h
index b3c3eef..f4fb16d 100644
--- a/chrome/browser/gtk/browser_toolbar_gtk.h
+++ b/chrome/browser/gtk/browser_toolbar_gtk.h
@@ -120,10 +120,6 @@ class BrowserToolbarGtk : public CommandUpdater::CommandObserver,
   // Gtk callback for the "clicked" signal.
   static void OnButtonClick(GtkWidget* button, BrowserToolbarGtk* toolbar);
 
-  // Gtk callback for the "button-release-event" signal.
-  static gboolean OnButtonRelease(GtkWidget* button, GdkEventButton* event,
-                                  BrowserToolbarGtk* toolbar);
-
   // Gtk callback to intercept mouse clicks to the menu buttons.
   static gboolean OnMenuButtonPressEvent(GtkWidget* button,
                                          GdkEventButton* event,
@@ -199,9 +195,6 @@ class BrowserToolbarGtk : public CommandUpdater::CommandObserver,
   // Controls whether or not a home button should be shown on the toolbar.
   BooleanPrefMember show_home_button_;
 
-  // The event state the last time we observed a button release event.
-  int last_release_event_flags_;
-
   NotificationRegistrar registrar_;
 
   // A GtkEntry that isn't part of the hierarchy. We keep this for native
diff --git a/chrome/browser/gtk/download_shelf_gtk.cc b/chrome/browser/gtk/download_shelf_gtk.cc
index 4606577..9601fd06 100644
--- a/chrome/browser/gtk/download_shelf_gtk.cc
+++ b/chrome/browser/gtk/download_shelf_gtk.cc
@@ -101,6 +101,7 @@ DownloadShelfGtk::DownloadShelfGtk(Browser* browser, GtkWidget* parent)
       GTK_CHROME_LINK_BUTTON(link_button), FALSE);
   g_signal_connect(link_button, "clicked",
                    G_CALLBACK(OnButtonClick), this);
+  gtk_util::SetButtonTriggersNavigation(link_button);
   // Until we switch to vector graphics, force the font size.
   // 13.4px == 10pt @ 96dpi
   gtk_util::ForceFontSizePixels(GTK_CHROME_LINK_BUTTON(link_button)->label,
diff --git a/chrome/browser/gtk/go_button_gtk.cc b/chrome/browser/gtk/go_button_gtk.cc
index ec9f594..a976a5c 100644
--- a/chrome/browser/gtk/go_button_gtk.cc
+++ b/chrome/browser/gtk/go_button_gtk.cc
@@ -13,6 +13,7 @@
 #include "chrome/browser/gtk/gtk_theme_provider.h"
 #include "chrome/browser/gtk/location_bar_view_gtk.h"
 #include "chrome/browser/profile.h"
+#include "chrome/common/gtk_util.h"
 #include "chrome/common/notification_service.h"
 #include "grit/generated_resources.h"
 #include "grit/theme_resources.h"
@@ -49,6 +50,7 @@ GoButtonGtk::GoButtonGtk(LocationBarViewGtk* location_bar, Browser* browser)
   GTK_WIDGET_UNSET_FLAGS(widget_.get(), GTK_CAN_FOCUS);
 
   SetTooltip();
+  gtk_util::SetButtonTriggersNavigation(widget());
 
   if (theme_provider_) {
     theme_provider_->InitThemesFor(this);
@@ -146,8 +148,12 @@ gboolean GoButtonGtk::OnClicked(GtkButton* widget, GoButtonGtk* button) {
     button->ChangeMode(MODE_GO, true);
   } else if (button->visible_mode_ == MODE_GO && button->stop_timer_.empty()) {
     // If the go button is visible and not within the double click timer, go.
-    if (button->browser_)
-      button->browser_->ExecuteCommand(IDC_GO);
+    GdkEventButton* event =
+        reinterpret_cast<GdkEventButton*>(gtk_get_current_event());
+    if (button->browser_) {
+      button->browser_->ExecuteCommandWithDisposition(IDC_GO,
+          event_utils::DispositionFromEventFlags(event->state));
+    }
 
     // Figure out the system double-click time.
     if (button->button_delay_ == 0) {
diff --git a/chrome/browser/gtk/gtk_chrome_link_button.cc b/chrome/browser/gtk/gtk_chrome_link_button.cc
index 735dec6..d4c7fb2 100644
--- a/chrome/browser/gtk/gtk_chrome_link_button.cc
+++ b/chrome/browser/gtk/gtk_chrome_link_button.cc
@@ -120,39 +120,6 @@ static gboolean gtk_chrome_link_button_expose(GtkWidget* widget,
   return TRUE;
 }
 
-static gboolean gtk_chrome_link_button_button_press(GtkWidget* widget,
-                                                    GdkEventButton* event) {
-  GtkButton* button;
-
-  if (event->type == GDK_BUTTON_PRESS) {
-    button = GTK_BUTTON(widget);
-
-    if (button->focus_on_click && !GTK_WIDGET_HAS_FOCUS (widget))
-      gtk_widget_grab_focus(widget);
-
-    if (event->button == 1 || event->button == 2)
-      gtk_button_pressed(button);
-  }
-
-  return TRUE;
-}
-
-static gboolean gtk_chrome_link_button_button_release(GtkWidget* widget,
-                                                      GdkEventButton* event) {
-  GtkButton* button = GTK_BUTTON(widget);
-  GtkChromeLinkButton* link_button = GTK_CHROME_LINK_BUTTON(widget);
-
-  free(link_button->click_button_event);
-  link_button->click_button_event = static_cast<GdkEventButton*>(
-      malloc(sizeof(GdkEventButton)));
-  *link_button->click_button_event = *event;
-
-  if (event->button == 1 || event->button == 2)
-    gtk_button_released(button);
-
-  return TRUE;
-}
-
 static void gtk_chrome_link_button_enter(GtkButton* button) {
   GtkWidget* widget = GTK_WIDGET(button);
   GtkChromeLinkButton* link_button = GTK_CHROME_LINK_BUTTON(button);
@@ -161,10 +128,7 @@ static void gtk_chrome_link_button_enter(GtkButton* button) {
 
 static void gtk_chrome_link_button_leave(GtkButton* button) {
   GtkWidget* widget = GTK_WIDGET(button);
-  GtkChromeLinkButton* link_button = GTK_CHROME_LINK_BUTTON(button);
   gdk_window_set_cursor(widget->window, NULL);
-  free(link_button->click_button_event);
-  link_button->click_button_event = NULL;
 }
 
 static void gtk_chrome_link_button_destroy(GtkObject* object) {
@@ -185,9 +149,6 @@ static void gtk_chrome_link_button_destroy(GtkObject* object) {
     button->hand_cursor = NULL;
   }
 
-  free(button->click_button_event);
-  button->click_button_event = NULL;
-
   free(button->text);
   button->text = NULL;
 
@@ -203,8 +164,6 @@ static void gtk_chrome_link_button_class_init(
   GtkObjectClass* object_class =
       reinterpret_cast<GtkObjectClass*>(link_button_class);
   widget_class->expose_event = &gtk_chrome_link_button_expose;
-  widget_class->button_press_event = &gtk_chrome_link_button_button_press;
-  widget_class->button_release_event = &gtk_chrome_link_button_button_release;
   button_class->enter = &gtk_chrome_link_button_enter;
   button_class->leave = &gtk_chrome_link_button_leave;
   object_class->destroy = &gtk_chrome_link_button_destroy;
@@ -223,7 +182,6 @@ static void gtk_chrome_link_button_init(GtkChromeLinkButton* button) {
   button->native_markup = NULL;
   button->using_native_theme = TRUE;
   button->hand_cursor = gdk_cursor_new(GDK_HAND2);
-  button->click_button_event = NULL;
   button->text = NULL;
 
   gtk_container_add(GTK_CONTAINER(button), button->label);
@@ -254,9 +212,4 @@ void gtk_chrome_link_button_set_use_gtk_theme(GtkChromeLinkButton* button,
   }
 }
 
-const GdkEventButton* gtk_chrome_link_button_get_event_for_click(
-    GtkChromeLinkButton* button) {
-  return button->click_button_event;
-}
-
 G_END_DECLS
diff --git a/chrome/browser/gtk/gtk_chrome_link_button.h b/chrome/browser/gtk/gtk_chrome_link_button.h
index e8cf891..adc6771 100644
--- a/chrome/browser/gtk/gtk_chrome_link_button.h
+++ b/chrome/browser/gtk/gtk_chrome_link_button.h
@@ -43,7 +43,6 @@ struct _GtkChromeLinkButton {
   gchar* native_markup;
   gboolean using_native_theme;
   GdkCursor* hand_cursor;
-  GdkEventButton* click_button_event;
   gchar* text;
   gboolean uses_markup;
 };
@@ -63,12 +62,6 @@ GtkWidget* gtk_chrome_link_button_new_with_markup(const char* markup);
 void gtk_chrome_link_button_set_use_gtk_theme(GtkChromeLinkButton* button,
                                               gboolean use_gtk);
 
-// Call this from within a "clicked" handler to get the release event that
-// triggered the click. It will return NULL if the click was triggered by a
-// keyboard event.
-const GdkEventButton* gtk_chrome_link_button_get_event_for_click(
-    GtkChromeLinkButton* button);
-
 GType gtk_chrome_link_button_get_type();
 
 G_END_DECLS
diff --git a/chrome/browser/gtk/infobar_gtk.cc b/chrome/browser/gtk/infobar_gtk.cc
index 47aa247..5ca91ea 100644
--- a/chrome/browser/gtk/infobar_gtk.cc
+++ b/chrome/browser/gtk/infobar_gtk.cc
@@ -188,6 +188,7 @@ class LinkInfoBar : public InfoBar {
         GTK_CHROME_LINK_BUTTON(link_button), FALSE);
     g_signal_connect(link_button, "clicked",
                      G_CALLBACK(OnLinkClick), this);
+    gtk_util::SetButtonTriggersNavigation(link_button);
 
     // If link_offset is npos, we right-align the link instead of embedding it
     // in the text.
@@ -220,8 +221,7 @@ class LinkInfoBar : public InfoBar {
  private:
   static void OnLinkClick(GtkWidget* button, LinkInfoBar* link_info_bar) {
     const GdkEventButton* button_click_event =
-        gtk_chrome_link_button_get_event_for_click(
-            GTK_CHROME_LINK_BUTTON(button));
+        reinterpret_cast<GdkEventButton*>(gtk_get_current_event());
     WindowOpenDisposition disposition = CURRENT_TAB;
     if (button_click_event) {
       disposition = event_utils::DispositionFromEventFlags(