Enabling page visibility api in the chrome browser.

content/browser/tab_contents/tab_contents.cc

Index: content/browser/tab_contents/tab_contents.cc
diff --git a/content/browser/tab_contents/tab_contents.cc b/content/browser/tab_contents/tab_contents.cc
index b4aee7c962069e04e147b0f2dde59dcc90f04a92..62f98826a4358ddd1990e9b095ad0f1786282cf9 100644
--- a/content/browser/tab_contents/tab_contents.cc
+++ b/content/browser/tab_contents/tab_contents.cc
@@ -180,6 +180,7 @@ ViewMsg_Navigate_Type::Value GetNavigationType(
 void MakeNavigateParams(const NavigationEntry& entry,
                         const NavigationController& controller,
                         NavigationController::ReloadType reload_type,
+                        bool is_hidden,
                         ViewMsg_Navigate_Params* params) {
   params->page_id = entry.page_id();
   params->pending_history_list_offset = controller.GetIndexOfEntry(&entry);
@@ -191,6 +192,7 @@ void MakeNavigateParams(const NavigationEntry& entry,
   params->state = entry.content_state();
   params->navigation_type =
       GetNavigationType(controller.profile(), entry, reload_type);
+  params->is_hidden = is_hidden;
   params->request_time = base::Time::Now();
 }
 
@@ -236,7 +238,8 @@ TabContents::TabContents(Profile* profile,
       maximum_zoom_percent_(
           static_cast<int>(WebKit::WebView::maxTextSizeMultiplier * 100)),
       temporary_zoom_settings_(false),
-      content_restrictions_(0) {
+      content_restrictions_(0),
+      is_initially_hidden_(false) {
   renderer_preferences_util::UpdateFromSystemSettings(
       &renderer_preferences_, profile);
 
@@ -508,6 +511,8 @@ void TabContents::DidBecomeSelected() {
 }
 
 void TabContents::WasHidden() {
+  is_initially_hidden_ = true;
+
   if (!capturing_contents()) {
     // |render_view_host()| can be NULL if the user middle clicks a link to open
     // a tab in then background, then closes the tab before selecting it.  This
@@ -608,7 +613,8 @@ bool TabContents::NavigateToEntry(
 
   // Navigate in the desired RenderViewHost.
   ViewMsg_Navigate_Params navigate_params;
-  MakeNavigateParams(entry, controller_, reload_type, &navigate_params);
+  MakeNavigateParams(entry, controller_, reload_type,
+                     IsHidden(), &navigate_params);
   if (delegate_) {
     navigate_params.extra_headers =
         delegate_->GetNavigationHeaders(navigate_params.url);
@@ -2040,6 +2046,12 @@ void TabContents::RequestDesktopNotificationPermission(
       render_view_host()->routing_id(), callback_context, this);
 }
 
+bool TabContents::IsHidden() const {
+  if (delegate())
+    return delegate()->IsHidden(this);
+  return is_initially_hidden_;
+}
+
 void TabContents::BeforeUnloadFiredFromRenderManager(
     bool proceed,
     bool* proceed_to_fire_unload) {