Support chrome.windows extension API events for browserless Panels.

chrome/browser/extensions/extension_panel_event_router.h

+// 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.
+
+#ifndef CHROME_BROWSER_EXTENSIONS_EXTENSION_PANEL_EVENT_ROUTER_H_
+#define CHROME_BROWSER_EXTENSIONS_EXTENSION_PANEL_EVENT_ROUTER_H_
+
+#include "base/basictypes.h"
+
+class Panel;
+class Profile;
+
+namespace base {
+class ListValue;
+}
+
+// The ExtensinoPanelEventRouter sends Panel window events

[Mihai Parparita -not on Chrome, 2012/07/19 20:14:58]

Typo ("Extensino")

+// to listeners inside extension process renderers.
+class ExtensionPanelEventRouter {

[Mihai Parparita -not on Chrome, 2012/07/19 20:14:58]

In light of http://crrev.com/147083, this perhaps should go in the extensions
namespace (then you can just call it PanelEventRouter).

Steven had stronger opinions on namespaces, I've cc-ed him on this review.

A more important question for Steven is whether ExtensionPanelEventRouter and
ExtensionBrowserEventRouter should share code, the way that window
implementations do (via BaseWindow). OnPanelActiveStatusChanged is complex
enough (and is nearly identical to OnBrowserSetLastActive) that I would prefer
to see either a BaseExtensionWindowEventRouter class that they both inherit
from, or a ExtensionWindowEventRouterHelper class that they use composition
with.

[stevenjb, 2012/07/20 16:54:33]

I think this should be extensions::PanelEventRouter. 

I looked through ExtensionBrowserEventRouter, and it really does look like that
could become WindowControllerEventRouter with all references to Browser replaced
with ExtensionWindowController. Then the same code should work for panels also.
I believe that BrowserList in BrowserEventRouter could be replaced with
WindowControllerList (which may need to have an observer list added) and also
work with both Browser and Panel.

I'm not sure we need to do that re-factoring here, but it does seem like it
would avoid a lot of duplicate code, which would definitely be preferable.

[jennb, 2012/07/20 18:09:37]

I propose creating extension::WindowEventRouter (these are chrome.windows.*
events). ExtensionBrowserEventRouter will only generate chrome.tabs.* events).
There's no need for a PanelEventRouter because the WindowEventRouter would
suffice. We also won't need hooks in Panel class as WindowEventRouter could be a
WindowControllerList observer.

I'll proceed with this plan unless anyone objects.

[stevenjb, 2012/07/20 18:26:14]

That sounds great to me, thanks!

+ public:
+  explicit ExtensionPanelEventRouter(Profile* profile);
+  virtual ~ExtensionPanelEventRouter();
+
+  // Sends corresponding events to listeners in extension process renderers.
+  void OnPanelOpened(Panel* panel);
+  void OnPanelActiveStatusChanged(Panel* panel, bool is_active_now);
+  void OnPanelClosed(Panel* panel);
+
+ private:
+  void DispatchEvent(const char* event_name,
+                     Profile* profile,
+                     base::ListValue* args);
+
+  // The main profile that owns this event router.
+  Profile* profile_;
+
+  // The profile the currently focused panel belongs to; either the main or
+  // incognito profile or NULL (none of the above). We remember this in order
+  // to correctly handle focus changes between non-OTR and OTR panels.
+  Profile* focused_profile_;
+
+  // The currently focused panel. We keep this so as to avoid sending multiple
+  // windows.onFocusChanged events with the same windowId.
+  int focused_window_id_;
+
+  DISALLOW_COPY_AND_ASSIGN(ExtensionPanelEventRouter);
+};
+
+#endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_PANEL_EVENT_ROUTER_H_