First part of remembering platform app window geometry.

chrome/browser/extensions/shell_window_geometry_cache.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_SHELL_WINDOW_GEOMETRY_CACHE_H_
+#define CHROME_BROWSER_EXTENSIONS_SHELL_WINDOW_GEOMETRY_CACHE_H_
+
+#include <map>
+#include <set>
+#include <string>
+
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/timer.h"
+#include "base/values.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+#include "ui/gfx/rect.h"
+
+class Profile;
+
+namespace extensions {
+
+class StateStore;
+
+// A cache for persisted geometry of shell windows, both to not have to wait
+// for IO when creating a new window, and to not cause IO on every window
+// geometry change

[asargent_no_longer_on_chrome, 2012/08/28 18:49:41]

nit: finish paragraph with a period.

[Marijn Kruisselbrink, 2012/08/28 22:14:58]

Done.

+class ShellWindowGeometryCache
+    : public base::SupportsWeakPtr<ShellWindowGeometryCache>,
+      public content::NotificationObserver {
+ public:
+  ShellWindowGeometryCache(Profile* profile, StateStore* state_store);
+
+  virtual ~ShellWindowGeometryCache();
+
+  void SaveWindowGeometry(const std::string& extension_id,

[asargent_no_longer_on_chrome, 2012/08/28 18:49:41]

optional suggestion: "SaveGeometry" and "GetGeometry" might be more concise
function names, since "Window" is already in the class name. 

[Marijn Kruisselbrink, 2012/08/28 22:14:58]

Done.

+                          const std::string& window_id,
+                          const gfx::Rect& bounds);
+
+  bool GetWindowGeometry(const std::string& extension_id,
+                         const std::string& window_id,
+                         gfx::Rect* bounds) const;
+
+ protected:
+  void OnExtensionLoaded(const std::string& extension_id);
+  void OnExtensionUnloaded(const std::string& extension_id);
+ private:
+  // content::NotificationObserver
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
+  void GeometryFromStorage(const std::string& extension_id,
+                           scoped_ptr<base::Value> value);
+
+  void SyncToStorage();
+
+  // State store.
+  StateStore* store_;
+
+  // Cached data
+  std::map<std::string, std::map<std::string, gfx::Rect> > cache_;
+
+  // Data that still needs saving
+  std::set<std::string> unsynced_extensions_;
+
+  // The timer used to save the data
+  base::OneShotTimer<ShellWindowGeometryCache> sync_timer_;
+
+  content::NotificationRegistrar registrar_;
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_SHELL_WINDOW_GEOMETRY_CACHE_H_