[GTK] Fix for muted tooltips while sound is playing.

chrome/browser/ui/gtk/tabs/tab_gtk.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/gtk/tabs/tab_gtk.h"
 
 #include <gdk/gdkkeysyms.h>
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
@@ skipping 280 matching lines @@
 
 ///////////////////////////////////////////////////////////////////////////////
 // TabGtk, private:
 
 void TabGtk::ContextMenuClosed() {
   delegate()->StopAllHighlighting();
   menu_controller_.reset();
 }
 
 void TabGtk::UpdateTooltipState() {
+  // Note: This method can be called several times per second for various
+  // reasons (e.g., navigation/loading state changes, tab media indicator
+  // updates, and so on).  However, we must avoid calling the
+  // gtk_widget_set_XXX() methods if there is no actual change in state.
+  // Otherwise, GTK will continuously re-hide *all* tooltips throughout the
+  // browser in response!  http://crbug.com/333002
+
   // Only show the tooltip if the title is truncated.
   if (title_width_ > title_bounds().width()) {
-    gtk_widget_set_tooltip_text(widget(),
-                                base::UTF16ToUTF8(GetTitle()).c_str());
+    const std::string utf8_title = base::UTF16ToUTF8(GetTitle());
+    if (gtk_widget_get_has_tooltip(widget())) {
+      gchar* const current_tooltip = gtk_widget_get_tooltip_text(widget());
+      if (current_tooltip) {
+        const bool title_unchanged = (utf8_title == current_tooltip);
+        g_free(current_tooltip);
+        if (title_unchanged)
+          return;
+      }
+    }
+    gtk_widget_set_tooltip_text(widget(), utf8_title.c_str());
   } else {
-    gtk_widget_set_has_tooltip(widget(), FALSE);
+    if (gtk_widget_get_has_tooltip(widget()))
+      gtk_widget_set_has_tooltip(widget(), FALSE);
   }
 }
 
 void TabGtk::CreateDragWidget() {
   DCHECK(!drag_widget_);
   drag_widget_ = gtk_invisible_new();
   g_signal_connect(drag_widget_, "drag-failed",
                    G_CALLBACK(OnDragFailedThunk), this);
   g_signal_connect(drag_widget_, "button-release-event",
                    G_CALLBACK(OnDragButtonReleasedThunk), this);
@@ skipping 41 matching lines @@
     gdk_event_free(last_mouse_down_);
     last_mouse_down_ = NULL;
   }
 
   // Notify the drag helper that we're done with any potential drag operations.
   // Clean up the drag helper, which is re-created on the next mouse press.
   delegate_->EndDrag(canceled);
 
   observer_.reset();
 }