Move ShellWindowGeometryCache into apps

BUG=159366

Review URL: https://chromiumcodereview.appspot.com/14636012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@200770 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 670 insertions, 0 deletions

diff --git a/apps/apps.gypi b/apps/apps.gypi
index 4867f73..6ba1011 100644
--- a/apps/apps.gypi
+++ b/apps/apps.gypi
@@ -42,6 +42,8 @@
         'pref_names.h',
         'prefs.cc',
         'prefs.h',
+        'shell_window_geometry_cache.cc',
+        'shell_window_geometry_cache.h',
         'shortcut_manager.cc',
         'shortcut_manager.h',
         'shortcut_manager_factory.cc',
diff --git a/apps/shell_window_geometry_cache.cc b/apps/shell_window_geometry_cache.cc
new file mode 100644
index 0000000..8a785b8
--- /dev/null
+++ b/apps/shell_window_geometry_cache.cc
@@ -0,0 +1,275 @@
+// 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 "apps/shell_window_geometry_cache.h"
+
+#include "base/bind.h"
+#include "base/stl_util.h"
+#include "base/strings/string_number_conversions.h"
+#include "chrome/browser/extensions/extension_prefs.h"
+#include "chrome/browser/extensions/extension_prefs_factory.h"
+#include "chrome/browser/profiles/incognito_helpers.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/profiles/profile_dependency_manager.h"
+#include "chrome/common/chrome_notification_types.h"
+#include "chrome/common/extensions/extension.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/notification_types.h"
+
+namespace {
+
+// The timeout in milliseconds before we'll persist window geometry to the
+// StateStore.
+const int kSyncTimeoutMilliseconds = 1000;
+
+} // namespace
+
+namespace apps {
+
+ShellWindowGeometryCache::ShellWindowGeometryCache(
+    Profile* profile, extensions::ExtensionPrefs* prefs)
+    : prefs_(prefs),
+      sync_delay_(base::TimeDelta::FromMilliseconds(kSyncTimeoutMilliseconds)) {
+  registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_LOADED,
+                 content::Source<Profile>(profile));
+  registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_UNLOADED,
+                 content::Source<Profile>(profile));
+}
+
+ShellWindowGeometryCache::~ShellWindowGeometryCache() {
+}
+
+// static
+ShellWindowGeometryCache* ShellWindowGeometryCache::Get(
+    content::BrowserContext* context) {
+  return Factory::GetForContext(context, true /* create */);
+}
+
+void ShellWindowGeometryCache::SaveGeometry(
+    const std::string& extension_id,
+    const std::string& window_id,
+    const gfx::Rect& bounds,
+    ui::WindowShowState window_state) {
+  ExtensionData& extension_data = cache_[extension_id];
+
+  // If we don't have any unsynced changes and this is a duplicate of what's
+  // already in the cache, just ignore it.
+  if (extension_data[window_id].bounds == bounds &&
+      extension_data[window_id].window_state == window_state &&
+      !ContainsKey(unsynced_extensions_, extension_id))
+    return;
+
+  base::Time now = base::Time::Now();
+
+  extension_data[window_id].bounds = bounds;
+  extension_data[window_id].window_state = window_state;
+  extension_data[window_id].last_change = now;
+
+  if (extension_data.size() > kMaxCachedWindows) {
+    ExtensionData::iterator oldest = extension_data.end();
+    // Too many windows in the cache, find the oldest one to remove.
+    for (ExtensionData::iterator it = extension_data.begin();
+         it != extension_data.end(); ++it) {
+      // Don't expunge the window that was just added.
+      if (it->first == window_id) continue;
+
+      // If time is in the future, reset it to now to minimize weirdness.
+      if (it->second.last_change > now)
+        it->second.last_change = now;
+
+      if (oldest == extension_data.end() ||
+          it->second.last_change < oldest->second.last_change)
+        oldest = it;
+    }
+    extension_data.erase(oldest);
+  }
+
+  unsynced_extensions_.insert(extension_id);
+
+  // We don't use Reset() because the timer may not yet be running.
+  // (In that case Stop() is a no-op.)
+  sync_timer_.Stop();
+  sync_timer_.Start(FROM_HERE, sync_delay_, this,
+                    &ShellWindowGeometryCache::SyncToStorage);
+}
+
+void ShellWindowGeometryCache::SyncToStorage() {
+  std::set<std::string> tosync;
+  tosync.swap(unsynced_extensions_);
+  for (std::set<std::string>::const_iterator it = tosync.begin(),
+      eit = tosync.end(); it != eit; ++it) {
+    const std::string& extension_id = *it;
+    const ExtensionData& extension_data = cache_[extension_id];
+
+    scoped_ptr<base::DictionaryValue> dict(new base::DictionaryValue);
+    for (ExtensionData::const_iterator it = extension_data.begin(),
+         eit = extension_data.end(); it != eit; ++it) {
+      base::DictionaryValue* value = new base::DictionaryValue;
+      const gfx::Rect& bounds = it->second.bounds;
+      value->SetInteger("x", bounds.x());
+      value->SetInteger("y", bounds.y());
+      value->SetInteger("w", bounds.width());
+      value->SetInteger("h", bounds.height());
+      value->SetInteger("state", it->second.window_state);
+      value->SetString(
+          "ts", base::Int64ToString(it->second.last_change.ToInternalValue()));
+      dict->SetWithoutPathExpansion(it->first, value);
+    }
+    prefs_->SetGeometryCache(extension_id, dict.Pass());
+  }
+}
+
+bool ShellWindowGeometryCache::GetGeometry(
+    const std::string& extension_id,
+    const std::string& window_id,
+    gfx::Rect* bounds,
+    ui::WindowShowState* window_state) const {
+
+  std::map<std::string, ExtensionData>::const_iterator
+      extension_data_it = cache_.find(extension_id);
+
+  // Not in the map means loading data for the extension didn't finish yet.
+  if (extension_data_it == cache_.end())
+    return false;
+
+  ExtensionData::const_iterator window_data = extension_data_it->second.find(
+      window_id);
+
+  if (window_data == extension_data_it->second.end())
+    return false;
+
+  if (bounds)
+    *bounds = window_data->second.bounds;
+  if (window_state)
+    *window_state = window_data->second.window_state;
+  return true;
+}
+
+void ShellWindowGeometryCache::Shutdown() {
+  SyncToStorage();
+}
+
+void ShellWindowGeometryCache::Observe(
+    int type, const content::NotificationSource& source,
+    const content::NotificationDetails& details) {
+  switch (type) {
+    case chrome::NOTIFICATION_EXTENSION_LOADED: {
+      std::string extension_id =
+          content::Details<const extensions::Extension>(details).ptr()->id();
+      OnExtensionLoaded(extension_id);
+      break;
+    }
+    case chrome::NOTIFICATION_EXTENSION_UNLOADED: {
+      std::string extension_id =
+          content::Details<const extensions::UnloadedExtensionInfo>(details).
+              ptr()->extension->id();
+      OnExtensionUnloaded(extension_id);
+      break;
+    }
+    default:
+      NOTREACHED();
+      return;
+  }
+}
+
+void ShellWindowGeometryCache::SetSyncDelayForTests(int timeout_ms) {
+  sync_delay_ = base::TimeDelta::FromMilliseconds(timeout_ms);
+}
+
+void ShellWindowGeometryCache::OnExtensionLoaded(
+    const std::string& extension_id) {
+  ExtensionData& extension_data = cache_[extension_id];
+
+  const base::DictionaryValue* stored_windows =
+      prefs_->GetGeometryCache(extension_id);
+  if (!stored_windows)
+    return;
+
+  for (base::DictionaryValue::Iterator it(*stored_windows); !it.IsAtEnd();
+       it.Advance()) {
+    // If the cache already contains geometry for this window, don't
+    // overwrite that information since it is probably the result of an
+    // application starting up very quickly.
+    const std::string& window_id = it.key();
+    ExtensionData::iterator cached_window = extension_data.find(window_id);
+    if (cached_window == extension_data.end()) {
+      const base::DictionaryValue* stored_window;
+      if (it.value().GetAsDictionary(&stored_window)) {
+        WindowData& window_data = extension_data[it.key()];
+
+        int i;
+        if (stored_window->GetInteger("x", &i))
+          window_data.bounds.set_x(i);
+        if (stored_window->GetInteger("y", &i))
+          window_data.bounds.set_y(i);
+        if (stored_window->GetInteger("w", &i))
+          window_data.bounds.set_width(i);
+        if (stored_window->GetInteger("h", &i))
+          window_data.bounds.set_height(i);
+        if (stored_window->GetInteger("state", &i)) {
+          window_data.window_state =
+              static_cast<ui::WindowShowState>(i);
+        }
+        std::string ts_as_string;
+        if (stored_window->GetString("ts", &ts_as_string)) {
+          int64 ts;
+          if (base::StringToInt64(ts_as_string, &ts)) {
+            window_data.last_change = base::Time::FromInternalValue(ts);
+          }
+        }
+      }
+    }
+  }
+}
+
+void ShellWindowGeometryCache::OnExtensionUnloaded(
+    const std::string& extension_id) {
+  SyncToStorage();
+  cache_.erase(extension_id);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// Factory boilerplate
+
+// static
+ShellWindowGeometryCache* ShellWindowGeometryCache::Factory::GetForContext(
+    content::BrowserContext* context, bool create) {
+  return static_cast<ShellWindowGeometryCache*>(
+      GetInstance()->GetServiceForProfile(context, create));
+}
+
+ShellWindowGeometryCache::Factory*
+ShellWindowGeometryCache::Factory::GetInstance() {
+  return Singleton<ShellWindowGeometryCache::Factory>::get();
+}
+
+ShellWindowGeometryCache::Factory::Factory()
+    : ProfileKeyedServiceFactory("ShellWindowGeometryCache",
+                                 ProfileDependencyManager::GetInstance()) {
+  DependsOn(extensions::ExtensionPrefsFactory::GetInstance());
+}
+
+ShellWindowGeometryCache::Factory::~Factory() {
+}
+
+ProfileKeyedService*
+ShellWindowGeometryCache::Factory::BuildServiceInstanceFor(
+    content::BrowserContext* context) const {
+  Profile* profile = Profile::FromBrowserContext(context);
+  return new ShellWindowGeometryCache(
+      profile,
+      extensions::ExtensionPrefs::Get(profile));
+}
+
+bool ShellWindowGeometryCache::Factory::ServiceIsNULLWhileTesting() const {
+  return false;
+}
+
+content::BrowserContext*
+ShellWindowGeometryCache::Factory::GetBrowserContextToUse(
+    content::BrowserContext* context) const {
+  return chrome::GetBrowserContextRedirectedInIncognito(context);
+}
+
+} // namespace apps
diff --git a/apps/shell_window_geometry_cache.h b/apps/shell_window_geometry_cache.h
new file mode 100644
index 0000000..5b5bb1d
--- /dev/null
+++ b/apps/shell_window_geometry_cache.h
@@ -0,0 +1,137 @@
+// 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/singleton.h"
+#include "base/time.h"
+#include "base/timer.h"
+#include "base/values.h"
+#include "chrome/browser/profiles/profile_keyed_service.h"
+#include "chrome/browser/profiles/profile_keyed_service_factory.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+#include "ui/base/ui_base_types.h"
+#include "ui/gfx/rect.h"
+
+class Profile;
+
+namespace extensions {
+class ExtensionPrefs;
+}
+
+namespace apps {
+
+// 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.
+class ShellWindowGeometryCache
+    : public ProfileKeyedService,
+      public content::NotificationObserver {
+ public:
+  class Factory : public ProfileKeyedServiceFactory {
+   public:
+    static ShellWindowGeometryCache* GetForContext(
+        content::BrowserContext* context,
+        bool create);
+
+    static Factory* GetInstance();
+   private:
+    friend struct DefaultSingletonTraits<Factory>;
+
+    Factory();
+    virtual ~Factory();
+
+    // ProfileKeyedServiceFactory
+    virtual ProfileKeyedService* BuildServiceInstanceFor(
+        content::BrowserContext* context) const OVERRIDE;
+    virtual bool ServiceIsNULLWhileTesting() const OVERRIDE;
+    virtual content::BrowserContext* GetBrowserContextToUse(
+        content::BrowserContext* context) const OVERRIDE;
+  };
+
+  ShellWindowGeometryCache(Profile* profile,
+                           extensions::ExtensionPrefs* prefs);
+
+  virtual ~ShellWindowGeometryCache();
+
+  // Returns the instance for the given browsing context.
+  static ShellWindowGeometryCache* Get(content::BrowserContext* context);
+
+  // Save the geometry and state associated with |extension_id| and |window_id|.
+  void SaveGeometry(const std::string& extension_id,
+                    const std::string& window_id,
+                    const gfx::Rect& bounds,
+                    ui::WindowShowState state);
+
+  // Get any saved geometry and state associated with |extension_id| and
+  // |window_id|. If saved data exists, sets |bounds| and |state| if not NULL
+  // and returns true.
+  bool GetGeometry(const std::string& extension_id,
+                   const std::string& window_id,
+                   gfx::Rect* bounds,
+                   ui::WindowShowState* state) const;
+
+  // ProfileKeyedService
+  virtual void Shutdown() OVERRIDE;
+
+  // Maximum number of windows we'll cache the geometry for per app.
+  static const size_t kMaxCachedWindows = 100;
+
+ protected:
+  friend class ShellWindowGeometryCacheTest;
+
+  // For tests, this modifies the timeout delay for saving changes from calls
+  // to SaveGeometry. (Note that even if this is set to 0, you still need to
+  // run the message loop to see the results of any SyncToStorage call).
+  void SetSyncDelayForTests(int timeout_ms);
+
+ private:
+  // Data stored for each window.
+  struct WindowData {
+    WindowData() : window_state(ui::SHOW_STATE_DEFAULT) {}
+    gfx::Rect bounds;
+    ui::WindowShowState window_state;
+    base::Time last_change;
+  };
+
+  // Data stored for each extension.
+  typedef std::map<std::string, WindowData> ExtensionData;
+
+  // content::NotificationObserver
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
+  void OnExtensionLoaded(const std::string& extension_id);
+  void OnExtensionUnloaded(const std::string& extension_id);
+  void SyncToStorage();
+
+  // Preferences storage.
+  extensions::ExtensionPrefs* prefs_;
+
+  // Cached data
+  std::map<std::string, ExtensionData> cache_;
+
+  // Data that still needs saving
+  std::set<std::string> unsynced_extensions_;
+
+  // The timer used to save the data
+  base::OneShotTimer<ShellWindowGeometryCache> sync_timer_;
+
+  // The timeout value we'll use for |sync_timer_|.
+  base::TimeDelta sync_delay_;
+
+  content::NotificationRegistrar registrar_;
+};
+
+}  // namespace apps
+
+#endif  // CHROME_BROWSER_EXTENSIONS_SHELL_WINDOW_GEOMETRY_CACHE_H_
diff --git a/apps/shell_window_geometry_cache_unittest.cc b/apps/shell_window_geometry_cache_unittest.cc
new file mode 100644
index 0000000..255c78c
--- /dev/null
+++ b/apps/shell_window_geometry_cache_unittest.cc
@@ -0,0 +1,256 @@
+// 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 "apps/shell_window_geometry_cache.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/prefs/mock_pref_change_callback.h"
+#include "base/strings/string_number_conversions.h"
+#include "chrome/browser/extensions/extension_prefs.h"
+#include "chrome/browser/extensions/test_extension_prefs.h"
+#include "chrome/test/base/testing_profile.h"
+#include "content/public/test/test_browser_thread.h"
+#include "content/public/test/test_utils.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace {
+  static const char kWindowId[] = "windowid";
+  static const char kWindowId2[] = "windowid2";
+
+  const char kWindowGeometryKey[] = "window_geometry";
+} // namespace
+
+using content::BrowserThread;
+
+namespace apps {
+
+// Base class for tests.
+class ShellWindowGeometryCacheTest : public testing::Test {
+ public:
+  ShellWindowGeometryCacheTest() :
+        ui_thread_(BrowserThread::UI, &ui_message_loop_) {
+    prefs_.reset(new extensions::TestExtensionPrefs(
+        ui_message_loop_.message_loop_proxy()));
+    cache_.reset(
+        new ShellWindowGeometryCache(&profile_, prefs_->prefs()));
+    cache_->SetSyncDelayForTests(0);
+  }
+
+  void AddGeometryAndLoadExtension(
+      const std::string& extension_id,
+      const std::string& window_id,
+      const gfx::Rect& bounds,
+      ui::WindowShowState state);
+
+  // Spins the UI threads' message loops to make sure any task
+  // posted to sync the geometry to the value store gets a chance to run.
+  void WaitForSync();
+
+  void LoadExtension(const std::string& extension_id);
+  void UnloadExtension(const std::string& extension_id);
+
+ protected:
+  TestingProfile profile_;
+  MessageLoopForUI ui_message_loop_;
+  content::TestBrowserThread ui_thread_;
+  scoped_ptr<extensions::TestExtensionPrefs> prefs_;
+  scoped_ptr<ShellWindowGeometryCache> cache_;
+};
+
+void ShellWindowGeometryCacheTest::AddGeometryAndLoadExtension(
+    const std::string& extension_id,
+    const std::string& window_id,
+    const gfx::Rect& bounds,
+    ui::WindowShowState state) {
+  scoped_ptr<base::DictionaryValue> dict(new base::DictionaryValue);
+  base::DictionaryValue* value = new base::DictionaryValue;
+  value->SetInteger("x", bounds.x());
+  value->SetInteger("y", bounds.y());
+  value->SetInteger("w", bounds.width());
+  value->SetInteger("h", bounds.height());
+  value->SetInteger("state", state);
+  dict->SetWithoutPathExpansion(window_id, value);
+  prefs_->prefs()->SetGeometryCache(extension_id, dict.Pass());
+  LoadExtension(extension_id);
+}
+
+void ShellWindowGeometryCacheTest::WaitForSync() {
+  content::RunAllPendingInMessageLoop();
+}
+
+void ShellWindowGeometryCacheTest::LoadExtension(
+    const std::string& extension_id) {
+  cache_->OnExtensionLoaded(extension_id);
+  WaitForSync();
+}
+
+void ShellWindowGeometryCacheTest::UnloadExtension(
+    const std::string& extension_id) {
+  cache_->OnExtensionUnloaded(extension_id);
+  WaitForSync();
+}
+
+// Test getting geometry from an empty store.
+TEST_F(ShellWindowGeometryCacheTest, GetGeometryEmptyStore) {
+  const std::string extension_id = prefs_->AddExtensionAndReturnId("ext1");
+  ASSERT_FALSE(cache_->GetGeometry(extension_id, kWindowId, NULL, NULL));
+}
+
+// Test getting geometry for an unknown extension.
+TEST_F(ShellWindowGeometryCacheTest, GetGeometryUnkownExtension) {
+  const std::string extension_id1 = prefs_->AddExtensionAndReturnId("ext1");
+  const std::string extension_id2 = prefs_->AddExtensionAndReturnId("ext2");
+  AddGeometryAndLoadExtension(extension_id1, kWindowId,
+                              gfx::Rect(4, 5, 31, 43),
+                              ui::SHOW_STATE_DEFAULT);
+  ASSERT_FALSE(cache_->GetGeometry(extension_id2, kWindowId, NULL, NULL));
+}
+
+// Test getting geometry for an unknown window in a known extension.
+TEST_F(ShellWindowGeometryCacheTest, GetGeometryUnkownWindow) {
+  const std::string extension_id = prefs_->AddExtensionAndReturnId("ext1");
+  AddGeometryAndLoadExtension(extension_id, kWindowId,
+                              gfx::Rect(4, 5, 31, 43),
+                              ui::SHOW_STATE_DEFAULT);
+  ASSERT_FALSE(cache_->GetGeometry(extension_id, kWindowId2, NULL, NULL));
+}
+
+// Test that loading geometry and state from the store works correctly.
+TEST_F(ShellWindowGeometryCacheTest, GetGeometryAndStateFromStore) {
+  const std::string extension_id = prefs_->AddExtensionAndReturnId("ext1");
+  gfx::Rect bounds(4, 5, 31, 43);
+  ui::WindowShowState state = ui::SHOW_STATE_NORMAL;
+  AddGeometryAndLoadExtension(extension_id, kWindowId, bounds, state);
+  gfx::Rect new_bounds;
+  ui::WindowShowState new_state = ui::SHOW_STATE_DEFAULT;
+  ASSERT_TRUE(cache_->GetGeometry(
+      extension_id, kWindowId, &new_bounds, &new_state));
+  ASSERT_EQ(bounds, new_bounds);
+  ASSERT_EQ(state, new_state);
+}
+
+// Test saving geometry and state to the cache and state store, and reading
+// it back.
+TEST_F(ShellWindowGeometryCacheTest, SaveGeometryAndStateToStore) {
+  const std::string extension_id = prefs_->AddExtensionAndReturnId("ext1");
+  const std::string window_id(kWindowId);
+
+  // inform cache of extension
+  LoadExtension(extension_id);
+
+  // update geometry stored in cache
+  gfx::Rect bounds(4, 5, 31, 43);
+  ui::WindowShowState state = ui::SHOW_STATE_NORMAL;
+  cache_->SaveGeometry(extension_id, window_id, bounds, state);
+
+  // make sure that immediately reading back geometry works
+  gfx::Rect new_bounds;
+  ui::WindowShowState new_state = ui::SHOW_STATE_DEFAULT;
+  ASSERT_TRUE(cache_->GetGeometry(
+      extension_id, window_id, &new_bounds, &new_state));
+  ASSERT_EQ(bounds, new_bounds);
+  ASSERT_EQ(state, new_state);
+
+  // unload extension to force cache to save data to the state store
+  UnloadExtension(extension_id);
+
+  // check if geometry got stored correctly in the state store
+  const base::DictionaryValue* dict =
+      prefs_->prefs()->GetGeometryCache(extension_id);
+  ASSERT_TRUE(dict);
+
+  ASSERT_TRUE(dict->HasKey(window_id));
+  int v;
+  ASSERT_TRUE(dict->GetInteger(window_id + ".x", &v));
+  ASSERT_EQ(bounds.x(), v);
+  ASSERT_TRUE(dict->GetInteger(window_id + ".y", &v));
+  ASSERT_EQ(bounds.y(), v);
+  ASSERT_TRUE(dict->GetInteger(window_id + ".w", &v));
+  ASSERT_EQ(bounds.width(), v);
+  ASSERT_TRUE(dict->GetInteger(window_id + ".h", &v));
+  ASSERT_EQ(bounds.height(), v);
+  ASSERT_TRUE(dict->GetInteger(window_id + ".state", &v));
+  ASSERT_EQ(state, v);
+
+  // check to make sure cache indeed doesn't know about this extension anymore
+  ASSERT_FALSE(cache_->GetGeometry(
+      extension_id, window_id, &new_bounds, &new_state));
+
+  // reload extension
+  LoadExtension(extension_id);
+  // and make sure the geometry got reloaded properly too
+  ASSERT_TRUE(cache_->GetGeometry(
+      extension_id, window_id, &new_bounds, &new_state));
+  ASSERT_EQ(bounds, new_bounds);
+  ASSERT_EQ(state, new_state);
+}
+
+// Tests that we won't do writes to the state store for SaveGeometry calls
+// which don't change the state we already have.
+TEST_F(ShellWindowGeometryCacheTest, NoDuplicateWrites) {
+  using testing::_;
+  using testing::Mock;
+
+  const std::string extension_id = prefs_->AddExtensionAndReturnId("ext1");
+  gfx::Rect bounds1(100, 200, 300, 400);
+  gfx::Rect bounds2(200, 400, 600, 800);
+  gfx::Rect bounds2_duplicate(200, 400, 600, 800);
+
+  MockPrefChangeCallback observer(prefs_->pref_service());
+  PrefChangeRegistrar registrar;
+  registrar.Init(prefs_->pref_service());
+  registrar.Add("extensions.settings", observer.GetCallback());
+
+  // Write the first bounds - it should do > 0 writes.
+  EXPECT_CALL(observer, OnPreferenceChanged(_));
+  cache_->SaveGeometry(extension_id, kWindowId, bounds1,
+                       ui::SHOW_STATE_DEFAULT);
+  WaitForSync();
+  Mock::VerifyAndClearExpectations(&observer);
+
+  // Write a different bounds - it should also do > 0 writes.
+  EXPECT_CALL(observer, OnPreferenceChanged(_));
+  cache_->SaveGeometry(extension_id, kWindowId, bounds2,
+                       ui::SHOW_STATE_DEFAULT);
+  WaitForSync();
+  Mock::VerifyAndClearExpectations(&observer);
+
+  // Write a different state - it should also do > 0 writes.
+  EXPECT_CALL(observer, OnPreferenceChanged(_));
+  cache_->SaveGeometry(extension_id, kWindowId, bounds2,
+                       ui::SHOW_STATE_NORMAL);
+  WaitForSync();
+  Mock::VerifyAndClearExpectations(&observer);
+
+  // Write a bounds and state that's a duplicate of what we already have.
+  // This should not do any writes.
+  EXPECT_CALL(observer, OnPreferenceChanged(_)).Times(0);
+  cache_->SaveGeometry(extension_id, kWindowId, bounds2_duplicate,
+                       ui::SHOW_STATE_NORMAL);
+  WaitForSync();
+  Mock::VerifyAndClearExpectations(&observer);
+}
+
+// Tests that no more than kMaxCachedWindows windows will be cached.
+TEST_F(ShellWindowGeometryCacheTest, MaxWindows) {
+  const std::string extension_id = prefs_->AddExtensionAndReturnId("ext1");
+  // inform cache of extension
+  LoadExtension(extension_id);
+
+  gfx::Rect bounds(4, 5, 31, 43);
+  for (size_t i = 0; i < ShellWindowGeometryCache::kMaxCachedWindows + 1; ++i) {
+    std::string window_id = "window_" + base::IntToString(i);
+    cache_->SaveGeometry(extension_id, window_id, bounds,
+                         ui::SHOW_STATE_DEFAULT);
+  }
+
+  // The first added window should no longer have cached geometry.
+  EXPECT_FALSE(cache_->GetGeometry(extension_id, "window_0", NULL, NULL));
+  // All other windows should still exist.
+  for (size_t i = 1; i < ShellWindowGeometryCache::kMaxCachedWindows + 1; ++i) {
+    std::string window_id = "window_" + base::IntToString(i);
+    EXPECT_TRUE(cache_->GetGeometry(extension_id, window_id, NULL, NULL));
+  }
+}
+
+} // namespace extensions