Make Page Visibility API work when the browser window is visible or not

ui/aura/window.cc

Index: ui/aura/window.cc
diff --git a/ui/aura/window.cc b/ui/aura/window.cc
index ab1a2da85fca8ff6911f10333006355627a5c03e..a7e40ca13845e0b59b738865391b22ba3f697c32 100644
--- a/ui/aura/window.cc
+++ b/ui/aura/window.cc
@@ -952,9 +952,15 @@ void Window::SetVisible(bool visible) {
   if (delegate_)
     delegate_->OnWindowTargetVisibilityChanged(visible);
 
-  NotifyWindowVisibilityChanged(this, visible);
+  NotifyWindowVisibilityChanged(this, visible, false);
 }
 
+#if defined(OS_LINUX)
+void Window::SetPageVisibility(bool visible) {
+  NotifyWindowVisibilityChanged(this, visible, true);
+}
+#endif
+
 void Window::SchedulePaint() {
   SchedulePaintInRect(gfx::Rect(0, 0, bounds().width(), bounds().height()));
 }
@@ -1282,28 +1288,32 @@ void Window::NotifyWindowHierarchyChangeAtReceiver(
 }
 
 void Window::NotifyWindowVisibilityChanged(aura::Window* target,
-                                           bool visible) {
-  if (!NotifyWindowVisibilityChangedDown(target, visible)) {
+                                           bool visible, bool content_visible) {
+  if (!NotifyWindowVisibilityChangedDown(target, visible, content_visible)) {
     return; // |this| has been deleted.
   }
   NotifyWindowVisibilityChangedUp(target, visible);
 }
 
 bool Window::NotifyWindowVisibilityChangedAtReceiver(aura::Window* target,
-                                                     bool visible) {
+                                                     bool visible,
+                                                     bool content_visible) {
   // |this| may be deleted during a call to OnWindowVisibilityChanged() on one
   // of the observers. We create an local observer for that. In that case we
   // exit without further access to any members.
   WindowTracker tracker;
   tracker.Add(this);
   FOR_EACH_OBSERVER(WindowObserver, observers_,
-                    OnWindowVisibilityChanged(target, visible));
+                    OnWindowVisibilityChanged(target, visible,
+                    content_visible));
   return tracker.Contains(this);
 }
 
 bool Window::NotifyWindowVisibilityChangedDown(aura::Window* target,
-                                               bool visible) {
-  if (!NotifyWindowVisibilityChangedAtReceiver(target, visible))
+                                               bool visible,
+                                               bool content_visible) {
+  if (!NotifyWindowVisibilityChangedAtReceiver(target, visible,
+        content_visible))
     return false; // |this| was deleted.
   std::set<const Window*> child_already_processed;
   bool child_destroyed = false;
@@ -1313,7 +1323,8 @@ bool Window::NotifyWindowVisibilityChangedDown(aura::Window* target,
          it != children_.end(); ++it) {
       if (!child_already_processed.insert(*it).second)
         continue;
-      if (!(*it)->NotifyWindowVisibilityChangedDown(target, visible)) {
+      if (!(*it)->NotifyWindowVisibilityChangedDown(target, visible,
+            content_visible)) {
         // |*it| was deleted, |it| is invalid and |children_| has changed.
         // We exit the current for-loop and enter a new one.
         child_destroyed = true;
@@ -1329,7 +1340,8 @@ void Window::NotifyWindowVisibilityChangedUp(aura::Window* target,
   // Start with the parent as we already notified |this|
   // in NotifyWindowVisibilityChangedDown.
   for (Window* window = parent(); window; window = window->parent()) {
-    bool ret = window->NotifyWindowVisibilityChangedAtReceiver(target, visible);
+    bool ret = window->NotifyWindowVisibilityChangedAtReceiver(target, visible,
+        false);
     DCHECK(ret);
   }
 }