Enabling page visibility api in the chrome browser.

content/renderer/render_view.cc

Index: content/renderer/render_view.cc
diff --git a/content/renderer/render_view.cc b/content/renderer/render_view.cc
index 012594724e5e9c40e78a31a48657a470a5eb1e6d..98716da8f6042b0eec880873cd616271221f61ed 100644
--- a/content/renderer/render_view.cc
+++ b/content/renderer/render_view.cc
@@ -717,6 +717,13 @@ void RenderView::OnNavigate(const ViewMsg_Navigate_Params& params) {
     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.
@@ -3879,6 +3886,7 @@ void RenderView::OnWasHidden() {
   if (webview()) {
     webview()->settings()->setMinimumTimerInterval(
         webkit_glue::kBackgroundTabTimerInterval);
+    webview()->setVisibilityState(WebKit::WebPageVisibilityStateHidden, false);
   }
 
 #if defined(OS_MACOSX)
@@ -3897,6 +3905,7 @@ void RenderView::OnWasRestored(bool needs_repainting) {
   if (webview()) {
     webview()->settings()->setMinimumTimerInterval(
         webkit_glue::kForegroundTabTimerInterval);
+    webview()->setVisibilityState(WebKit::WebPageVisibilityStateVisible, false);
   }
 
 #if defined(OS_MACOSX)
@@ -4097,6 +4106,14 @@ void RenderView::registerProtocolHandler(const WebString& scheme,
                                               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.