[Panels refactor] Track Panels in TaskManager now that they are not under the tab contents umbrella.

chrome/browser/ui/panels/panel.cc

Index: chrome/browser/ui/panels/panel.cc
diff --git a/chrome/browser/ui/panels/panel.cc b/chrome/browser/ui/panels/panel.cc
index 90f4ded2cef105fd4aa850791d8110303d52c14d..1f744530260b8e345b851b0e1cdc81b5e67bca7f 100644
--- a/chrome/browser/ui/panels/panel.cc
+++ b/chrome/browser/ui/panels/panel.cc
@@ -31,6 +31,13 @@
 using content::RenderViewHost;
 using content::UserMetricsAction;
 
+namespace {
+
+static base::LazyInstance<base::PropertyAccessor<Panel*> >
+    g_panel_property_accessor = LAZY_INSTANCE_INITIALIZER;
+
+}  // namespace
+
 namespace panel_internal {
 
 class PanelExtensionWindowController : public ExtensionWindowController {
@@ -113,6 +120,17 @@ Panel::~Panel() {
     browser::EndKeepAlive();
 }
 
+// static
+base::PropertyAccessor<Panel*>* Panel::property_accessor() {
+  return g_panel_property_accessor.Pointer();
+}
+
+// static
+Panel* Panel::FromWebContents(content::WebContents* contents) {
+  Panel** panel = property_accessor()->GetProperty(contents->GetPropertyBag());

[Dmitry Titov, 2012/07/18 22:52:15]

Seems a loop through PanelManager will be easier to read, smaller and not that
slow since we always have a very limited number of panels. 

+  return panel ? *panel : NULL;
+}
+
 void Panel::Initialize(const gfx::Rect& bounds, Browser* browser) {
   DCHECK(!initialized_);
   DCHECK(!panel_strip_);  // Cannot be added to a strip until fully created.
@@ -141,7 +159,14 @@ void Panel::Initialize(Profile* profile, const GURL& url,
   // Set up hosting for web contents.
   panel_host_.reset(new PanelHost(this, profile));
   panel_host_->Init(url);
-  native_panel_->AttachWebContents(GetWebContents());
+
+  // Stash this panel in the property bag so it can be retrieved without
+  // having to iterate through all panel manager.
+  content::WebContents* contents = GetWebContents();
+  if (contents) {

[Dmitry Titov, 2012/07/18 22:52:15]

can it be NULL? When?

+    property_accessor()->SetProperty(contents->GetPropertyBag(), this);
+    native_panel_->AttachWebContents(contents);
+  }
 
   // Close when the extension is unloaded or the browser is exiting.
   registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_UNLOADED,