gtk: Ask whether window is active from WM.

It could happpen that the WM thinks a window is active but it's actually not,
like when showing a context menu. In most cases we should follow what WM
says to keep consistent bevaviour on all platforms.

atom/browser/native_window_gtk.cc

@@ -16,6 +16,7 @@
 #include "content/public/common/renderer_preferences.h"
 #include "ui/base/accelerators/platform_accelerator_gtk.h"
 #include "ui/base/models/simple_menu_model.h"
+#include "ui/base/x/active_window_watcher_x.h"
 #include "ui/base/x/x11_util.h"
 #include "ui/gfx/gtk_util.h"
 #include "ui/gfx/rect.h"
@@ -39,6 +40,7 @@ NativeWindowGtk::NativeWindowGtk(content::WebContents* web_contents,
       vbox_(gtk_vbox_new(FALSE, 0)),
       state_(GDK_WINDOW_STATE_WITHDRAWN),
       is_always_on_top_(false),
+      is_active_(false),
       suppress_window_raise_(false),
       frame_cursor_(NULL) {
   gtk_container_add(GTK_CONTAINER(window_), vbox_);
@@ -53,6 +55,8 @@ NativeWindowGtk::NativeWindowGtk(content::WebContents* web_contents,
   if (!icon_.IsEmpty())
     gtk_window_set_icon(window_, icon_.ToGdkPixbuf());
 
+  ui::ActiveWindowWatcherX::AddObserver(this);
+
   // In some (older) versions of compiz, raising top-level windows when they
   // are partially off-screen causes them to get snapped back on screen, not
   // always even on the current virtual desktop.  If we are running under
@@ -109,6 +113,10 @@ void NativeWindowGtk::Focus(bool focus) {
 }
 
 bool NativeWindowGtk::IsFocused() {
+  if (ui::ActiveWindowWatcherX::WMSupportsActivation())
+    return is_active_;
+
+  // This still works even though we don't get the activation notification.
   return gtk_window_is_active(window_);
 }
 
@@ -290,6 +298,10 @@ void NativeWindowGtk::UpdateDraggableRegions(
   }
 }
 
+void NativeWindowGtk::ActiveWindowChanged(GdkWindow* active_window) {
+  is_active_ = gtk_widget_get_window(GTK_WIDGET(window_)) == active_window;
+}
+
 void NativeWindowGtk::RegisterAccelerators() {
   DCHECK(menu_);
   accelerator_table_.clear();

atom/browser/native_window_gtk.h

@@ -16,12 +16,14 @@
 #include "third_party/skia/include/core/SkRegion.h"
 #include "ui/base/accelerators/accelerator.h"
 #include "ui/base/gtk/gtk_signal.h"
+#include "ui/base/x/active_window_watcher_x_observer.h"
 #include "ui/gfx/size.h"
 
 namespace atom {
 
 class NativeWindowGtk : public NativeWindow,
-                        public MenuGtk::Delegate {
+                        public MenuGtk::Delegate,
+                        public ui::ActiveWindowWatcherXObserver {
  public:
   explicit NativeWindowGtk(content::WebContents* web_contents,
                            base::DictionaryValue* options);
@@ -69,6 +71,9 @@ class NativeWindowGtk : public NativeWindow,
   virtual void UpdateDraggableRegions(
       const std::vector<DraggableRegion>& regions) OVERRIDE;
 
+  // Overridden from ActiveWindowWatcherXObserver.
+  virtual void ActiveWindowChanged(GdkWindow* active_window) OVERRIDE;
+
  private:
   // Register accelerators supported by the menu model.
   void RegisterAccelerators();
@@ -111,6 +116,11 @@ class NativeWindowGtk : public NativeWindow,
   // clicked to maximize.
   scoped_ptr<SkRegion> draggable_region_;
 
+  // True if the window manager thinks the window is active. It could happpen
+  // that the WM thinks a window is active but it's actually not, like when
+  // showing a context menu.
+  bool is_active_;
+
   // If true, don't call gdk_window_raise() when we get a click in the title
   // bar or window border.  This is to work around a compiz bug.
   bool suppress_window_raise_;