Enabling page visibility api in the chrome browser.

content/renderer/render_view.cc

 // Copyright (c) 2011 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 "content/renderer/render_view.h"
 
 #include <algorithm>
 #include <cmath>
 #include <string>
 #include <vector>
@@ skipping 699 matching lines @@
 
   WebFrame* main_frame = webview()->mainFrame();
   if (is_reload && main_frame->currentHistoryItem().isNull()) {
     // We cannot reload if we do not have any history state.  This happens, for
     // example, when recovering from a crash.  Our workaround here is a bit of
     // a hack since it means that reload after a crashed tab does not cause an
     // end-to-end cache validation.
     is_reload = false;
   }
 
+  // Correct the visible state of the webview before loading a document.
+  if (params.is_hidden) {

[brettw, 2011/05/18 22:11:38]

Prefer no {} for single-line conditionals (prevailing style for this file).

How does the is_hidden_ variable in RenderWidget get updated? It seems like it
would be out of sync with the webkit visibility state in this case?

I realized this because I was wondering whether this call could be simplified to
  webview()->setVisibilityState(visibilityState(), true);

[Shishir, 2011/05/20 03:48:19]

Removed {} around condition.

At this point the is_hidden_ property in the renderer and the internal webkit
visibility do go out of sync. This happens because we always starts of renderers
in the visible state and later update them to the correct state. If the
navigation happens before the renderer has been updated, this will be out of
sync till its been updated with the right state. 

+    webview()->setVisibilityState(WebKit::WebPageVisibilityStateHidden, true);
+  } else {
+    webview()->setVisibilityState(WebKit::WebPageVisibilityStateVisible, true);
+  }
+
   // A navigation resulting from loading a javascript URL should not be treated
   // as a browser initiated event.  Instead, we want it to look as if the page
   // initiated any load resulting from JS execution.
   if (!params.url.SchemeIs(chrome::kJavaScriptScheme)) {
     NavigationState* state = NavigationState::CreateBrowserInitiated(
         params.page_id,
         params.pending_history_list_offset,
         params.transition,
         params.request_time);
     if (params.navigation_type == ViewMsg_Navigate_Type::RESTORE) {
@@ skipping 3142 matching lines @@
 void RenderView::DidHandleMouseEvent(const WebKit::WebMouseEvent& event) {
   FOR_EACH_OBSERVER(RenderViewObserver, observers_, DidHandleMouseEvent(event));
 }
 
 void RenderView::OnWasHidden() {
   RenderWidget::OnWasHidden();
 
   if (webview()) {
     webview()->settings()->setMinimumTimerInterval(
         webkit_glue::kBackgroundTabTimerInterval);
+    webview()->setVisibilityState(WebKit::WebPageVisibilityStateHidden, false);
   }
 
 #if defined(OS_MACOSX)
   // Inform plugins that their container is no longer visible.
   std::set<WebPluginDelegateProxy*>::iterator plugin_it;
   for (plugin_it = plugin_delegates_.begin();
        plugin_it != plugin_delegates_.end(); ++plugin_it) {
     (*plugin_it)->SetContainerVisibility(false);
   }
 #endif  // OS_MACOSX
 }
 
 void RenderView::OnWasRestored(bool needs_repainting) {
   RenderWidget::OnWasRestored(needs_repainting);
 
   if (webview()) {
     webview()->settings()->setMinimumTimerInterval(
         webkit_glue::kForegroundTabTimerInterval);
+    webview()->setVisibilityState(WebKit::WebPageVisibilityStateVisible, false);
   }
 
 #if defined(OS_MACOSX)
   // Inform plugins that their container is now visible.
   std::set<WebPluginDelegateProxy*>::iterator plugin_it;
   for (plugin_it = plugin_delegates_.begin();
        plugin_it != plugin_delegates_.end(); ++plugin_it) {
     (*plugin_it)->SetContainerVisibility(true);
   }
 #endif  // OS_MACOSX
@@ skipping 180 matching lines @@
   if (base.GetOrigin() != absolute_url.GetOrigin()) {
     return;
   }
   RenderThread::current()->Send(
       new ViewHostMsg_RegisterProtocolHandler(routing_id_,
                                               UTF16ToUTF8(scheme),
                                               absolute_url,
                                               title));
 }
 
+WebKit::WebPageVisibilityState RenderView::visibilityState() const {
+  if (is_hidden()) {

[brettw, 2011/05/18 22:11:38]

Ditto remove the {}

[Shishir, 2011/05/20 03:48:19]

Done.

+    return WebKit::WebPageVisibilityStateHidden;
+  } else {
+    return WebKit::WebPageVisibilityStateVisible;
+  }
+}
+
 bool RenderView::IsNonLocalTopLevelNavigation(
     const GURL& url, WebKit::WebFrame* frame, WebKit::WebNavigationType type) {
   // Must be a top level frame.
   if (frame->parent() != NULL)
     return false;
 
   // Navigations initiated within Webkit are not sent out to the external host
   // in the following cases.
   // 1. The url scheme is not http/https
   // 2. The origin of the url and the opener is the same in which case the
@@ skipping 73 matching lines @@
     const webkit_glue::CustomContextMenuContext& custom_context) {
   if (custom_context.is_pepper_menu)
     pepper_delegate_.OnContextMenuClosed(custom_context);
   else
     context_menu_node_.reset();
 }
 
 void RenderView::OnNetworkStateChanged(bool online) {
   WebNetworkStateNotifier::setOnLine(online);
 }