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

content/browser/web_contents/web_contents_impl.cc

 // Copyright (c) 2012 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/browser/web_contents/web_contents_impl.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
@@ skipping 1069 matching lines @@
   // Restore power save blocker if there are active video players running.
   if (!active_video_players_.empty() && !video_power_save_blocker_)
     CreateVideoPowerSaveBlocker();
 
   FOR_EACH_OBSERVER(WebContentsObserver, observers_, WasShown());
 
   should_normally_be_visible_ = true;
 }
 
 void WebContentsImpl::WasHidden() {
+  WasHidden(false);
+}
+
+void WebContentsImpl::WasHidden(bool content_visible) {
   // If there are entities capturing screenshots or video (e.g., mirroring),
   // don't activate the "disable rendering" optimization.
   if (capturer_count_ == 0) {
     // |GetRenderViewHost()| can be NULL if the user middle clicks a link to
     // open a tab in the background, then closes the tab before selecting it.
     // This is because closing the tab calls WebContentsImpl::Destroy(), which
     // removes the |GetRenderViewHost()|; then when we actually destroy the
     // window, OnWindowPosChanged() notices and calls WasHidden() (which
     // calls us).
     for (RenderWidgetHostView* view : GetRenderWidgetHostViewsInTree()) {
       if (view)
-        view->Hide();
+        view->Hide(content_visible);
     }
 
     // Release any video power save blockers held as video is not visible.
     video_power_save_blocker_.reset();
   }
 
   FOR_EACH_OBSERVER(WebContentsObserver, observers_, WasHidden());
 
   should_normally_be_visible_ = false;
 }
@@ skipping 3401 matching lines @@
   node->render_manager()->ResumeResponseDeferredAtStart();
 }
 
 void WebContentsImpl::SetForceDisableOverscrollContent(bool force_disable) {
   force_disable_overscroll_content_ = force_disable;
   if (view_)
     view_->SetOverscrollControllerEnabled(CanOverscrollContent());
 }
 
 }  // namespace content