Reducing CPU cycles of hidden/minimized browser windows

content/browser/web_contents/web_contents_view_aura.cc

Index: content/browser/web_contents/web_contents_view_aura.cc
diff --git a/content/browser/web_contents/web_contents_view_aura.cc b/content/browser/web_contents/web_contents_view_aura.cc
index 2b29df7cb821681df6c78a4951c2c92373e90803..ab1bfab65862550669eaf96d56fe0d0f1c169ebc 100644
--- a/content/browser/web_contents/web_contents_view_aura.cc
+++ b/content/browser/web_contents/web_contents_view_aura.cc
@@ -98,6 +98,17 @@ bool ShouldNavigateBack(const NavigationController& controller,
          controller.CanGoBack();
 }
 
+// Update the |web contents| to be |visible|.
+void UpdateWebContentsVisibility(WebContentsImpl* web_contents, bool visible) {
+  if (visible) {
+    if (!web_contents->should_normally_be_visible())
+      web_contents->WasShown();
+  } else {
+    if (web_contents->should_normally_be_visible())
+      web_contents->WasHidden();
+  }
+}
+
 RenderWidgetHostViewAura* ToRenderWidgetHostViewAura(
     RenderWidgetHostView* view) {
   if (!view || RenderViewHostFactory::has_factory())
@@ -718,6 +729,7 @@ WebContentsViewAura::~WebContentsViewAura() {
     return;
 
   window_observer_.reset();
+  window_->RemoveObserver(this);
 
   // Window needs a valid delegate during its destructor, so we explicitly
   // delete it here.
@@ -1045,6 +1057,7 @@ void WebContentsViewAura::CreateView(
   window_->SetType(ui::wm::WINDOW_TYPE_CONTROL);
   window_->SetTransparent(false);
   window_->Init(aura::WINDOW_LAYER_NOT_DRAWN);
+  window_->AddObserver(this);
   aura::Window* root_window = context ? context->GetRootWindow() : NULL;
   if (root_window) {
     // There are places where there is no context currently because object
@@ -1427,10 +1440,6 @@ void WebContentsViewAura::OnWindowDestroyed(aura::Window* window) {
 }
 
 void WebContentsViewAura::OnWindowTargetVisibilityChanged(bool visible) {
-  if (visible)
-    web_contents_->WasShown();
-  else
-    web_contents_->WasHidden();
 }
 
 bool WebContentsViewAura::HasHitTestMask() const {
@@ -1553,4 +1562,22 @@ int WebContentsViewAura::OnPerformDrop(const ui::DropTargetEvent& event) {
   return ConvertFromWeb(current_drag_op_);
 }
 
+void WebContentsViewAura::OnWindowParentChanged(aura::Window* window,
+                                                aura::Window* parent) {
+  // On Windows we will get called with a parent of NULL as part of the shut
+  // down process. As such we do only change the visibility when a parent gets
+  // set.
+  if (parent)
+    UpdateWebContentsVisibility(web_contents_, window->IsVisible());
+}
+
+void WebContentsViewAura::OnWindowVisibilityChanged(aura::Window* window,
+                                                    bool visible) {
+  // Ignore any visibility changes in the hierarchy below.
+  if (window != window_.get() && window_->Contains(window))
+    return;
+
+  UpdateWebContentsVisibility(web_contents_, visible);
+}
+
 }  // namespace content