Allow the user to choose which corner of the screen should get notifications.

BUG=none
TEST=create notifications, use the options menu

Review URL: http://codereview.chromium.org/6006007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@70564 0039d316-1c4b-4281-b951-d872f2087c98

17 files changed, 397 insertions, 42 deletions

diff --git a/chrome/browser/browser_process_impl.cc b/chrome/browser/browser_process_impl.cc
index 83fe028..222ee28 100644
--- a/chrome/browser/browser_process_impl.cc
+++ b/chrome/browser/browser_process_impl.cc
@@ -770,7 +770,8 @@ void BrowserProcessImpl::CreateIntranetRedirectDetector() {
 
 void BrowserProcessImpl::CreateNotificationUIManager() {
   DCHECK(notification_ui_manager_.get() == NULL);
-  notification_ui_manager_.reset(NotificationUIManager::Create());
+  notification_ui_manager_.reset(NotificationUIManager::Create(local_state()));
+
   created_notification_ui_manager_ = true;
 }
 
diff --git a/chrome/browser/chromeos/notifications/balloon_collection_impl.h b/chrome/browser/chromeos/notifications/balloon_collection_impl.h
index 03496df..320bfd6 100644
--- a/chrome/browser/chromeos/notifications/balloon_collection_impl.h
+++ b/chrome/browser/chromeos/notifications/balloon_collection_impl.h
@@ -66,6 +66,7 @@ class BalloonCollectionImpl : public BalloonCollection,
   virtual void RemoveAll();
   virtual bool HasSpace() const;
   virtual void ResizeBalloon(Balloon* balloon, const gfx::Size& size);
+  virtual void SetPositionPreference(PositionPreference position) {}
   virtual void DisplayChanged() {}
   virtual void OnBalloonClosed(Balloon* source);
   virtual const Balloons& GetActiveBalloons() { return base_.balloons(); }
diff --git a/chrome/browser/chromeos/notifications/desktop_notifications_unittest.cc b/chrome/browser/chromeos/notifications/desktop_notifications_unittest.cc
index 377828b..9a77680 100644
--- a/chrome/browser/chromeos/notifications/desktop_notifications_unittest.cc
+++ b/chrome/browser/chromeos/notifications/desktop_notifications_unittest.cc
@@ -7,6 +7,7 @@
 #include "base/stringprintf.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/common/render_messages_params.h"
+#include "chrome/test/testing_pref_service.h"
 
 namespace chromeos {
 
@@ -77,7 +78,8 @@ DesktopNotificationsTest::~DesktopNotificationsTest() {
 void DesktopNotificationsTest::SetUp() {
   profile_.reset(new TestingProfile());
   balloon_collection_ = new MockBalloonCollection();
-  ui_manager_.reset(new NotificationUIManager());
+  ui_manager_.reset(
+      new NotificationUIManager(profile_->GetTestingPrefService()));
   ui_manager_->Initialize(balloon_collection_);
   balloon_collection_->set_space_change_listener(ui_manager_.get());
   service_.reset(new DesktopNotificationService(profile(), ui_manager_.get()));
@@ -86,8 +88,8 @@ void DesktopNotificationsTest::SetUp() {
 
 void DesktopNotificationsTest::TearDown() {
   service_.reset(NULL);
-  profile_.reset(NULL);
   ui_manager_.reset(NULL);
+  profile_.reset(NULL);
 }
 
 ViewHostMsg_ShowNotification_Params
diff --git a/chrome/browser/notifications/balloon.h b/chrome/browser/notifications/balloon.h
index 3f4ba0b..5b86508 100644
--- a/chrome/browser/notifications/balloon.h
+++ b/chrome/browser/notifications/balloon.h
@@ -68,6 +68,8 @@ class Balloon {
   const gfx::Size& content_size() const { return content_size_; }
   void set_content_size(const gfx::Size& size) { content_size_ = size; }
 
+  const BalloonCollection* collection() const { return collection_; }
+
   const gfx::Size& min_scrollbar_size() const { return min_scrollbar_size_; }
   void set_min_scrollbar_size(const gfx::Size& size) {
     min_scrollbar_size_ = size;
diff --git a/chrome/browser/notifications/balloon_collection.cc b/chrome/browser/notifications/balloon_collection.cc
index 218126b..60c9f2d 100644
--- a/chrome/browser/notifications/balloon_collection.cc
+++ b/chrome/browser/notifications/balloon_collection.cc
@@ -28,20 +28,14 @@ const int kRepositionDelay = 300;
 
 }  // namespace
 
-// static
-// Note that on MacOS, since the coordinate system is inverted vertically from
-// the others, this actually produces notifications coming from the TOP right,
-// which is what is desired.
-BalloonCollectionImpl::Layout::Placement
-    BalloonCollectionImpl::Layout::placement_ =
-        Layout::VERTICALLY_FROM_BOTTOM_RIGHT;
-
 BalloonCollectionImpl::BalloonCollectionImpl()
 #if USE_OFFSETS
     : ALLOW_THIS_IN_INITIALIZER_LIST(reposition_factory_(this)),
       added_as_message_loop_observer_(false)
 #endif
 {
+
+  SetPositionPreference(BalloonCollection::DEFAULT_POSITION);
 }
 
 BalloonCollectionImpl::~BalloonCollectionImpl() {
@@ -221,26 +215,27 @@ void BalloonCollectionImpl::Layout::GetMaxLinearSize(int* max_balloon_size,
                                                      int* total_size) const {
   DCHECK(max_balloon_size && total_size);
 
-  switch (placement_) {
-    case VERTICALLY_FROM_TOP_RIGHT:
-    case VERTICALLY_FROM_BOTTOM_RIGHT:
-      *total_size = work_area_.height();
-      *max_balloon_size = max_balloon_height();
-      break;
-    default:
-      NOTREACHED();
-      break;
-  }
+  // All placement schemes are vertical, so we only care about height.
+  *total_size = work_area_.height();
+  *max_balloon_size = max_balloon_height();
 }
 
 gfx::Point BalloonCollectionImpl::Layout::GetLayoutOrigin() const {
   int x = 0;
   int y = 0;
   switch (placement_) {
+    case VERTICALLY_FROM_TOP_LEFT:
+      x = work_area_.x() + HorizontalEdgeMargin();
+      y = work_area_.y() + VerticalEdgeMargin();
+      break;
     case VERTICALLY_FROM_TOP_RIGHT:
       x = work_area_.right() - HorizontalEdgeMargin();
       y = work_area_.y() + VerticalEdgeMargin();
       break;
+    case VERTICALLY_FROM_BOTTOM_LEFT:
+      x = work_area_.x() + HorizontalEdgeMargin();
+      y = work_area_.bottom() - VerticalEdgeMargin();
+      break;
     case VERTICALLY_FROM_BOTTOM_RIGHT:
       x = work_area_.right() - HorizontalEdgeMargin();
       y = work_area_.bottom() - VerticalEdgeMargin();
@@ -260,12 +255,24 @@ gfx::Point BalloonCollectionImpl::Layout::NextPosition(
   int x = 0;
   int y = 0;
   switch (placement_) {
+    case VERTICALLY_FROM_TOP_LEFT:
+      x = position_iterator->x();
+      y = position_iterator->y();
+      position_iterator->set_y(position_iterator->y() + balloon_size.height() +
+                               InterBalloonMargin());
+      break;
     case VERTICALLY_FROM_TOP_RIGHT:
       x = position_iterator->x() - balloon_size.width();
       y = position_iterator->y();
       position_iterator->set_y(position_iterator->y() + balloon_size.height() +
                                InterBalloonMargin());
       break;
+    case VERTICALLY_FROM_BOTTOM_LEFT:
+      position_iterator->set_y(position_iterator->y() - balloon_size.height() -
+                               InterBalloonMargin());
+      x = position_iterator->x();
+      y = position_iterator->y();
+      break;
     case VERTICALLY_FROM_BOTTOM_RIGHT:
       position_iterator->set_y(position_iterator->y() - balloon_size.height() -
                                InterBalloonMargin());
@@ -283,10 +290,18 @@ gfx::Point BalloonCollectionImpl::Layout::OffScreenLocation() const {
   int x = 0;
   int y = 0;
   switch (placement_) {
+    case VERTICALLY_FROM_TOP_LEFT:
+      x = work_area_.x() + HorizontalEdgeMargin();
+      y = work_area_.y() + kBalloonMaxHeight + VerticalEdgeMargin();
+      break;
     case VERTICALLY_FROM_TOP_RIGHT:
       x = work_area_.right() - kBalloonMaxWidth - HorizontalEdgeMargin();
       y = work_area_.y() + kBalloonMaxHeight + VerticalEdgeMargin();
       break;
+    case VERTICALLY_FROM_BOTTOM_LEFT:
+      x = work_area_.x() + HorizontalEdgeMargin();
+      y = work_area_.bottom() + kBalloonMaxHeight + VerticalEdgeMargin();
+      break;
     case VERTICALLY_FROM_BOTTOM_RIGHT:
       x = work_area_.right() - kBalloonMaxWidth - HorizontalEdgeMargin();
       y = work_area_.bottom() + kBalloonMaxHeight + VerticalEdgeMargin();
diff --git a/chrome/browser/notifications/balloon_collection.h b/chrome/browser/notifications/balloon_collection.h
index 13875dc..6909759 100644
--- a/chrome/browser/notifications/balloon_collection.h
+++ b/chrome/browser/notifications/balloon_collection.h
@@ -34,6 +34,18 @@ class BalloonCollection {
     virtual void OnBalloonSpaceChanged() = 0;
   };
 
+  // Do not change existing values without migration path; these
+  // are stored as integers in user preferences.
+  enum PositionPreference {
+    UPPER_RIGHT        = 0,
+    LOWER_RIGHT        = 1,
+    UPPER_LEFT         = 2,
+    LOWER_LEFT         = 3,
+
+    // The default position is different on different platforms.
+    DEFAULT_POSITION   = -1
+  };
+
   static BalloonCollection* Create();
 
   BalloonCollection()
@@ -63,6 +75,9 @@ class BalloonCollection {
   // Request the resizing of a balloon.
   virtual void ResizeBalloon(Balloon* balloon, const gfx::Size& size) = 0;
 
+  // Set the position preference for the collection.
+  virtual void SetPositionPreference(PositionPreference position) = 0;
+
   // Update for new screen dimensions.
   virtual void DisplayChanged() = 0;
 
diff --git a/chrome/browser/notifications/balloon_collection_impl.h b/chrome/browser/notifications/balloon_collection_impl.h
index 7fb1ea9a..d123717 100644
--- a/chrome/browser/notifications/balloon_collection_impl.h
+++ b/chrome/browser/notifications/balloon_collection_impl.h
@@ -47,6 +47,7 @@ class BalloonCollectionImpl : public BalloonCollection
   virtual void RemoveAll();
   virtual bool HasSpace() const;
   virtual void ResizeBalloon(Balloon* balloon, const gfx::Size& size);
+  virtual void SetPositionPreference(PositionPreference position);
   virtual void DisplayChanged();
   virtual void OnBalloonClosed(Balloon* source);
   virtual const Balloons& GetActiveBalloons() { return base_.balloons(); }
@@ -68,6 +69,15 @@ class BalloonCollectionImpl : public BalloonCollection
    public:
     Layout();
 
+    // These enumerations all are based on a screen orientation where
+    // the origin is the top-left.
+    enum Placement {
+      VERTICALLY_FROM_TOP_LEFT,
+      VERTICALLY_FROM_TOP_RIGHT,
+      VERTICALLY_FROM_BOTTOM_LEFT,
+      VERTICALLY_FROM_BOTTOM_RIGHT
+    };
+
     // Refresh the work area and balloon placement.
     void OnDisplaySettingsChanged();
 
@@ -80,6 +90,8 @@ class BalloonCollectionImpl : public BalloonCollection
     // Utility function constrains the input rectangle to the min and max sizes.
     static gfx::Size ConstrainToSizeLimits(const gfx::Size& rect);
 
+    void set_placement(Placement placement) { placement_ = placement; }
+
     // Returns both the total space available and the maximum
     // allowed per balloon.
     //
@@ -109,11 +121,6 @@ class BalloonCollectionImpl : public BalloonCollection
     gfx::Point OffScreenLocation() const;
 
    private:
-    enum Placement {
-      VERTICALLY_FROM_TOP_RIGHT,
-      VERTICALLY_FROM_BOTTOM_RIGHT
-    };
-
     // Layout parameters
     int VerticalEdgeMargin() const;
     int HorizontalEdgeMargin() const;
@@ -125,7 +132,7 @@ class BalloonCollectionImpl : public BalloonCollection
     static const int kBalloonMinHeight = 24;
     static const int kBalloonMaxHeight = 160;
 
-    static Placement placement_;
+    Placement placement_;
     gfx::Rect work_area_;
     DISALLOW_COPY_AND_ASSIGN(Layout);
   };
diff --git a/chrome/browser/notifications/balloon_collection_linux.cc b/chrome/browser/notifications/balloon_collection_linux.cc
index 08354a0..099193c 100644
--- a/chrome/browser/notifications/balloon_collection_linux.cc
+++ b/chrome/browser/notifications/balloon_collection_linux.cc
@@ -67,6 +67,27 @@ bool BalloonCollectionImpl::IsCursorInBalloonCollection() const {
   return bounds.Contains(cursor);
 }
 
+void BalloonCollectionImpl::SetPositionPreference(
+    PositionPreference position) {
+  if (position == DEFAULT_POSITION)
+    position = LOWER_RIGHT;
+
+  // All positioning schemes are vertical, and linux
+  // uses the normal screen orientation.
+  if (position == UPPER_RIGHT)
+    layout_.set_placement(Layout::VERTICALLY_FROM_TOP_RIGHT);
+  else if (position == UPPER_LEFT)
+    layout_.set_placement(Layout::VERTICALLY_FROM_TOP_LEFT);
+  else if (position == LOWER_LEFT)
+    layout_.set_placement(Layout::VERTICALLY_FROM_BOTTOM_LEFT);
+  else if (position == LOWER_RIGHT)
+    layout_.set_placement(Layout::VERTICALLY_FROM_BOTTOM_RIGHT);
+  else
+    NOTREACHED();
+
+  PositionBalloons(true);
+}
+
 // static
 BalloonCollection* BalloonCollection::Create() {
   return new BalloonCollectionImpl();
diff --git a/chrome/browser/notifications/balloon_collection_mac.mm b/chrome/browser/notifications/balloon_collection_mac.mm
index 7615415..d31bc39 100644
--- a/chrome/browser/notifications/balloon_collection_mac.mm
+++ b/chrome/browser/notifications/balloon_collection_mac.mm
@@ -43,6 +43,27 @@ void BalloonCollectionImpl::PositionBalloons(bool reposition) {
   [NSAnimationContext endGrouping];
 }
 
+void BalloonCollectionImpl::SetPositionPreference(
+    PositionPreference position) {
+  if (position == DEFAULT_POSITION)
+    position = UPPER_RIGHT;
+
+  // All positioning schemes are vertical, but mac
+  // uses a vertically reversed screen orientation.
+  if (position == UPPER_RIGHT)
+    layout_.set_placement(Layout::VERTICALLY_FROM_BOTTOM_RIGHT);
+  else if (position == UPPER_LEFT)
+    layout_.set_placement(Layout::VERTICALLY_FROM_BOTTOM_LEFT);
+  else if (position == LOWER_LEFT)
+    layout_.set_placement(Layout::VERTICALLY_FROM_TOP_LEFT);
+  else if (position == LOWER_RIGHT)
+    layout_.set_placement(Layout::VERTICALLY_FROM_TOP_RIGHT);
+  else
+    NOTREACHED();
+
+  PositionBalloons(true);
+}
+
 // static
 BalloonCollection* BalloonCollection::Create() {
   return new BalloonCollectionImpl();
diff --git a/chrome/browser/notifications/balloon_collection_win.cc b/chrome/browser/notifications/balloon_collection_win.cc
index 07bcd18..742872b 100644
--- a/chrome/browser/notifications/balloon_collection_win.cc
+++ b/chrome/browser/notifications/balloon_collection_win.cc
@@ -62,6 +62,27 @@ bool BalloonCollectionImpl::IsCursorInBalloonCollection() const {
   return bounds.Contains(cursor);
 }
 
+void BalloonCollectionImpl::SetPositionPreference(
+    PositionPreference position) {
+  if (position == DEFAULT_POSITION)
+    position = LOWER_RIGHT;
+
+  // All positioning schemes are vertical, and windows
+  // uses the normal screen orientation.
+  if (position == UPPER_RIGHT)
+    layout_.set_placement(Layout::VERTICALLY_FROM_TOP_RIGHT);
+  else if (position == UPPER_LEFT)
+    layout_.set_placement(Layout::VERTICALLY_FROM_TOP_LEFT);
+  else if (position == LOWER_LEFT)
+    layout_.set_placement(Layout::VERTICALLY_FROM_BOTTOM_LEFT);
+  else if (position == LOWER_RIGHT)
+    layout_.set_placement(Layout::VERTICALLY_FROM_BOTTOM_RIGHT);
+  else
+    NOTREACHED();
+
+  PositionBalloons(true);
+}
+
 // static
 BalloonCollection* BalloonCollection::Create() {
   return new BalloonCollectionImpl();
diff --git a/chrome/browser/notifications/desktop_notifications_unittest.cc b/chrome/browser/notifications/desktop_notifications_unittest.cc
index ebb6ab8..762990f 100644
--- a/chrome/browser/notifications/desktop_notifications_unittest.cc
+++ b/chrome/browser/notifications/desktop_notifications_unittest.cc
@@ -6,7 +6,9 @@
 
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
+#include "chrome/common/pref_names.h"
 #include "chrome/common/render_messages_params.h"
+#include "chrome/test/testing_pref_service.h"
 
 // static
 const int MockBalloonCollection::kMockBalloonSpace = 5;
@@ -69,7 +71,8 @@ DesktopNotificationsTest::~DesktopNotificationsTest() {
 void DesktopNotificationsTest::SetUp() {
   profile_.reset(new TestingProfile());
   balloon_collection_ = new MockBalloonCollection();
-  ui_manager_.reset(new NotificationUIManager());
+  ui_manager_.reset(
+      new NotificationUIManager(profile_->GetTestingPrefService()));
   ui_manager_->Initialize(balloon_collection_);
   balloon_collection_->set_space_change_listener(ui_manager_.get());
   service_.reset(new DesktopNotificationService(profile(), ui_manager_.get()));
@@ -78,8 +81,8 @@ void DesktopNotificationsTest::SetUp() {
 
 void DesktopNotificationsTest::TearDown() {
   service_.reset(NULL);
-  profile_.reset(NULL);
   ui_manager_.reset(NULL);
+  profile_.reset(NULL);
 }
 
 ViewHostMsg_ShowNotification_Params
@@ -320,3 +323,77 @@ TEST_F(DesktopNotificationsTest, TestUserInputEscaping) {
   EXPECT_EQ(std::string::npos, data_url.spec().find("%3cscript%3e"));
   EXPECT_EQ(std::string::npos, data_url.spec().find("%3ci%3e"));
 }
+
+TEST_F(DesktopNotificationsTest, TestPositionPreference) {
+  // Set position preference to lower right.
+  profile_->GetPrefs()->SetInteger(prefs::kDesktopNotificationPosition,
+                                   BalloonCollection::LOWER_RIGHT);
+
+  // Create some notifications.
+  ViewHostMsg_ShowNotification_Params params = StandardTestNotification();
+  for (int id = 0; id <= 3; ++id) {
+    params.notification_id = id;
+    EXPECT_TRUE(service_->ShowDesktopNotification(
+        params, 0, 0, DesktopNotificationService::PageNotification));
+  }
+
+  std::deque<Balloon*>& balloons = balloon_collection_->balloons();
+  std::deque<Balloon*>::iterator iter;
+
+  // Check that they decrease in y-position (for MAC, with reversed
+  // coordinates, they should increase).
+  int last_y = -1;
+  int last_x = -1;
+
+  for (iter = balloons.begin(); iter != balloons.end(); ++iter) {
+    int current_x = (*iter)->GetPosition().x();
+    int current_y = (*iter)->GetPosition().y();
+    if (last_x > 0)
+      EXPECT_EQ(last_x, current_x);
+
+    if (last_y > 0) {
+#if defined(OS_MACOSX)
+      EXPECT_GT(current_y, last_y);
+#else
+      EXPECT_LT(current_y, last_y);
+#endif
+    }
+
+    last_x = current_x;
+    last_y = current_y;
+  }
+
+  // Now change the position to upper right.  This should cause an immediate
+  // repositioning, and we check for the reverse ordering.
+  profile_->GetPrefs()->SetInteger(prefs::kDesktopNotificationPosition,
+                                   BalloonCollection::UPPER_RIGHT);
+  last_x = -1;
+  last_y = -1;
+
+  for (iter = balloons.begin(); iter != balloons.end(); ++iter) {
+    int current_x = (*iter)->GetPosition().x();
+    int current_y = (*iter)->GetPosition().y();
+
+    if (last_x > 0)
+      EXPECT_EQ(last_x, current_x);
+
+    if (last_y > 0) {
+#if defined(OS_MACOSX)
+      EXPECT_LT(current_y, last_y);
+#else
+      EXPECT_GT(current_y, last_y);
+#endif
+    }
+
+    last_x = current_x;
+    last_y = current_y;
+  }
+
+  // Now change the position to upper left.  Confirm that the X value for the
+  // balloons gets smaller.
+  profile_->GetPrefs()->SetInteger(prefs::kDesktopNotificationPosition,
+                                   BalloonCollection::UPPER_LEFT);
+
+  int current_x = (*balloons.begin())->GetPosition().x();
+  EXPECT_LT(current_x, last_x);
+}
diff --git a/chrome/browser/notifications/notification_options_menu_model.cc b/chrome/browser/notifications/notification_options_menu_model.cc
index 45620c9..fb05bda 100644
--- a/chrome/browser/notifications/notification_options_menu_model.cc
+++ b/chrome/browser/notifications/notification_options_menu_model.cc
@@ -7,10 +7,14 @@
 #include "app/l10n_util.h"
 #include "base/compiler_specific.h"
 #include "base/logging.h"
+#include "base/utf_string_conversions.h"
 #include "chrome/browser/browser_list.h"
+#include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/notifications/balloon_collection.h"
 #include "chrome/browser/notifications/desktop_notification_service.h"
 #include "chrome/browser/notifications/notification.h"
+#include "chrome/browser/notifications/notification_ui_manager.h"
 #include "chrome/browser/notifications/notifications_prefs_cache.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/chrome_switches.h"
@@ -27,6 +31,89 @@
 const int kTogglePermissionCommand = 0;
 const int kToggleExtensionCommand = 1;
 const int kOpenContentSettingsCommand = 2;
+const int kCornerSelectionSubMenu = 3;
+
+const int kCornerGroupId = 10;
+const int kCornerUpperLeft = 11;
+const int kCornerUpperRight = 12;
+const int kCornerLowerLeft = 13;
+const int kCornerLowerRight = 14;
+const int kCornerDefault = 20;
+
+CornerSelectionMenuModel::CornerSelectionMenuModel(Balloon* balloon)
+    : ALLOW_THIS_IN_INITIALIZER_LIST(menus::SimpleMenuModel(this)),
+      balloon_(balloon) {
+  AddRadioItem(kCornerDefault,
+               l10n_util::GetStringUTF16(IDS_NOTIFICATION_POSITION_DEFAULT),
+               kCornerGroupId);
+  AddSeparator();
+  AddRadioItem(kCornerUpperLeft,
+               l10n_util::GetStringUTF16(IDS_NOTIFICATION_POSITION_UPPER_LEFT),
+               kCornerGroupId);
+  AddRadioItem(kCornerUpperRight,
+               l10n_util::GetStringUTF16(IDS_NOTIFICATION_POSITION_UPPER_RIGHT),
+               kCornerGroupId);
+  AddRadioItem(kCornerLowerLeft,
+               l10n_util::GetStringUTF16(IDS_NOTIFICATION_POSITION_LOWER_LEFT),
+               kCornerGroupId);
+  AddRadioItem(kCornerLowerRight,
+               l10n_util::GetStringUTF16(IDS_NOTIFICATION_POSITION_LOWER_RIGHT),
+               kCornerGroupId);
+}
+
+CornerSelectionMenuModel::~CornerSelectionMenuModel() {
+}
+
+bool CornerSelectionMenuModel::IsCommandIdChecked(int command_id) const {
+  NotificationUIManager* ui = g_browser_process->notification_ui_manager();
+  BalloonCollection::PositionPreference current = ui->GetPositionPreference();
+
+  LOG(INFO) << "Current position preference: " << current;
+
+  if (command_id == kCornerUpperLeft)
+    return (current == BalloonCollection::UPPER_LEFT);
+  else if (command_id == kCornerUpperRight)
+    return (current == BalloonCollection::UPPER_RIGHT);
+  else if (command_id == kCornerLowerLeft)
+    return (current == BalloonCollection::LOWER_LEFT);
+  else if (command_id == kCornerLowerRight)
+    return (current == BalloonCollection::LOWER_RIGHT);
+  else if (command_id == kCornerDefault)
+    return (current == BalloonCollection::DEFAULT_POSITION);
+
+  NOTREACHED();
+  return false;
+}
+
+bool CornerSelectionMenuModel::IsCommandIdEnabled(int command_id) const {
+  // All the menu options are always enabled.
+  return true;
+}
+
+bool CornerSelectionMenuModel::GetAcceleratorForCommandId(
+    int command_id, menus::Accelerator* accelerator) {
+  // Currently no accelerators.
+  return false;
+}
+
+void CornerSelectionMenuModel::ExecuteCommand(int command_id) {
+  NotificationUIManager* ui = g_browser_process->notification_ui_manager();
+
+  LOG(INFO) << "Executing command: " << command_id;
+
+  if (command_id == kCornerUpperLeft)
+    ui->SetPositionPreference(BalloonCollection::UPPER_LEFT);
+  else if (command_id == kCornerUpperRight)
+    ui->SetPositionPreference(BalloonCollection::UPPER_RIGHT);
+  else if (command_id == kCornerLowerLeft)
+    ui->SetPositionPreference(BalloonCollection::LOWER_LEFT);
+  else if (command_id == kCornerLowerRight)
+    ui->SetPositionPreference(BalloonCollection::LOWER_RIGHT);
+  else if (command_id == kCornerDefault)
+    ui->SetPositionPreference(BalloonCollection::DEFAULT_POSITION);
+  else
+    NOTREACHED();
+}
 
 NotificationOptionsMenuModel::NotificationOptionsMenuModel(Balloon* balloon)
     : ALLOW_THIS_IN_INITIALIZER_LIST(menus::SimpleMenuModel(this)),
@@ -49,6 +136,11 @@ NotificationOptionsMenuModel::NotificationOptionsMenuModel(Balloon* balloon)
   const string16 settings_label = l10n_util::GetStringUTF16(
       IDS_NOTIFICATIONS_SETTINGS_BUTTON);
   AddItem(kOpenContentSettingsCommand, settings_label);
+
+  corner_menu_model_.reset(new CornerSelectionMenuModel(balloon));
+  AddSubMenu(kCornerSelectionSubMenu,
+             l10n_util::GetStringUTF16(IDS_NOTIFICATION_CHOOSE_POSITION),
+             corner_menu_model_.get());
 }
 
 NotificationOptionsMenuModel::~NotificationOptionsMenuModel() {
diff --git a/chrome/browser/notifications/notification_options_menu_model.h b/chrome/browser/notifications/notification_options_menu_model.h
index f7f4c77..022b7e0 100644
--- a/chrome/browser/notifications/notification_options_menu_model.h
+++ b/chrome/browser/notifications/notification_options_menu_model.h
@@ -9,6 +9,28 @@
 #include "app/menus/simple_menu_model.h"
 #include "chrome/browser/notifications/balloon.h"
 
+// Model for the corner-selection submenu.
+class CornerSelectionMenuModel : public menus::SimpleMenuModel,
+                                 public menus::SimpleMenuModel::Delegate {
+ public:
+  explicit CornerSelectionMenuModel(Balloon* balloon);
+  virtual ~CornerSelectionMenuModel();
+
+  // Overridden from menus::SimpleMenuModel::Delegate:
+  virtual bool IsCommandIdChecked(int command_id) const;
+  virtual bool IsCommandIdEnabled(int command_id) const;
+  virtual bool GetAcceleratorForCommandId(int command_id,
+                                          menus::Accelerator* accelerator);
+  virtual void ExecuteCommand(int command_id);
+
+ private:
+  // Not owned.
+  Balloon* balloon_;
+
+  DISALLOW_COPY_AND_ASSIGN(CornerSelectionMenuModel);
+};
+
+// Model for the notification options menu itself.
 class NotificationOptionsMenuModel : public menus::SimpleMenuModel,
                                      public menus::SimpleMenuModel::Delegate {
  public:
@@ -29,6 +51,8 @@ class NotificationOptionsMenuModel : public menus::SimpleMenuModel,
  private:
   Balloon* balloon_; // Not owned.
 
+  scoped_ptr<CornerSelectionMenuModel> corner_menu_model_;
+
   DISALLOW_COPY_AND_ASSIGN(NotificationOptionsMenuModel);
 };
 
diff --git a/chrome/browser/notifications/notification_ui_manager.cc b/chrome/browser/notifications/notification_ui_manager.cc
index 6e2ff02..950bd6c 100644
--- a/chrome/browser/notifications/notification_ui_manager.cc
+++ b/chrome/browser/notifications/notification_ui_manager.cc
@@ -7,11 +7,14 @@
 #include "base/logging.h"
 #include "base/scoped_ptr.h"
 #include "base/stl_util-inl.h"
+#include "chrome/browser/browser_process.h"
 #include "chrome/browser/notifications/balloon_collection.h"
 #include "chrome/browser/notifications/notification.h"
+#include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/renderer_host/site_instance.h"
 #include "chrome/common/notification_service.h"
 #include "chrome/common/notification_type.h"
+#include "chrome/common/pref_names.h"
 
 // A class which represents a notification waiting to be shown.
 class QueuedNotification {
@@ -38,10 +41,11 @@ class QueuedNotification {
   DISALLOW_COPY_AND_ASSIGN(QueuedNotification);
 };
 
-NotificationUIManager::NotificationUIManager()
+NotificationUIManager::NotificationUIManager(PrefService* local_state)
     : balloon_collection_(NULL) {
   registrar_.Add(this, NotificationType::APP_TERMINATING,
                  NotificationService::AllSources());
+  position_pref_.Init(prefs::kDesktopNotificationPosition, local_state, this);
 }
 
 NotificationUIManager::~NotificationUIManager() {
@@ -49,14 +53,30 @@ NotificationUIManager::~NotificationUIManager() {
 }
 
 // static
-NotificationUIManager* NotificationUIManager::Create() {
+NotificationUIManager* NotificationUIManager::Create(PrefService* local_state) {
   BalloonCollection* balloons = BalloonCollection::Create();
-  NotificationUIManager* instance = new NotificationUIManager();
+  NotificationUIManager* instance = new NotificationUIManager(local_state);
   instance->Initialize(balloons);
   balloons->set_space_change_listener(instance);
   return instance;
 }
 
+// static
+void NotificationUIManager::RegisterPrefs(PrefService* prefs) {
+  prefs->RegisterIntegerPref(prefs::kDesktopNotificationPosition,
+                             BalloonCollection::DEFAULT_POSITION);
+}
+
+void NotificationUIManager::Initialize(
+    BalloonCollection* balloon_collection) {
+  DCHECK(!balloon_collection_.get());
+  DCHECK(balloon_collection);
+  balloon_collection_.reset(balloon_collection);
+  balloon_collection_->SetPositionPreference(
+      static_cast<BalloonCollection::PositionPreference>(
+          position_pref_.GetValue()));
+}
+
 void NotificationUIManager::Add(const Notification& notification,
                                 Profile* profile) {
   if (TryReplacement(notification)) {
@@ -157,11 +177,33 @@ bool NotificationUIManager::TryReplacement(const Notification& notification) {
   return false;
 }
 
+BalloonCollection::PositionPreference
+NotificationUIManager::GetPositionPreference() {
+  LOG(INFO) << "Current position preference: " << position_pref_.GetValue();
+
+  return static_cast<BalloonCollection::PositionPreference>(
+      position_pref_.GetValue());
+}
+
+void NotificationUIManager::SetPositionPreference(
+    BalloonCollection::PositionPreference preference) {
+  LOG(INFO) << "Setting position preference: " << preference;
+  position_pref_.SetValue(static_cast<int>(preference));
+  balloon_collection_->SetPositionPreference(preference);
+}
+
 void NotificationUIManager::Observe(NotificationType type,
                                     const NotificationSource& source,
                                     const NotificationDetails& details) {
-  if (type == NotificationType::APP_TERMINATING)
+  if (type == NotificationType::APP_TERMINATING) {
     CancelAll();
-  else
+  } else if (type == NotificationType::PREF_CHANGED) {
+    std::string* name = Details<std::string>(details).ptr();
+    if (*name == prefs::kDesktopNotificationPosition)
+      balloon_collection_->SetPositionPreference(
+          static_cast<BalloonCollection::PositionPreference>(
+              position_pref_.GetValue()));
+  } else {
     NOTREACHED();
+  }
 }
diff --git a/chrome/browser/notifications/notification_ui_manager.h b/chrome/browser/notifications/notification_ui_manager.h
index de429db..3a0125c 100644
--- a/chrome/browser/notifications/notification_ui_manager.h
+++ b/chrome/browser/notifications/notification_ui_manager.h
@@ -13,10 +13,12 @@
 #include "base/scoped_ptr.h"
 #include "chrome/browser/notifications/balloon.h"
 #include "chrome/browser/notifications/balloon_collection.h"
+#include "chrome/browser/prefs/pref_member.h"
 #include "chrome/common/notification_observer.h"
 #include "chrome/common/notification_registrar.h"
 
 class Notification;
+class PrefService;
 class Profile;
 class QueuedNotification;
 class SiteInstance;
@@ -27,21 +29,20 @@ class NotificationUIManager
     : public BalloonCollection::BalloonSpaceChangeListener,
       public NotificationObserver {
  public:
-  NotificationUIManager();
+  explicit NotificationUIManager(PrefService* local_state);
   virtual ~NotificationUIManager();
 
   // Creates an initialized UI manager with a new balloon collection
   // and the listener relationship setup.
   // Except for unit tests, this is the way to construct the object.
-  static NotificationUIManager* Create();
+  static NotificationUIManager* Create(PrefService* local_state);
+
+  // Registers preferences.
+  static void RegisterPrefs(PrefService* prefs);
 
   // Initializes the UI manager with a balloon collection; this object
   // takes ownership of the balloon collection.
-  void Initialize(BalloonCollection* balloon_collection) {
-    DCHECK(!balloon_collection_.get());
-    DCHECK(balloon_collection);
-    balloon_collection_.reset(balloon_collection);
-  }
+  void Initialize(BalloonCollection* balloon_collection);
 
   // Adds a notification to be displayed. Virtual for unit test override.
   virtual void Add(const Notification& notification,
@@ -65,6 +66,13 @@ class NotificationUIManager
     return balloon_collection_.get();
   }
 
+  // Gets the preference indicating where notifications should be placed.
+  BalloonCollection::PositionPreference GetPositionPreference();
+
+  // Sets the preference that indicates where notifications should
+  // be placed on the screen.
+  void SetPositionPreference(BalloonCollection::PositionPreference preference);
+
   // NotificationObserver interface (the event signaling kind of notifications)
   virtual void Observe(NotificationType type,
                        const NotificationSource& source,
@@ -95,6 +103,9 @@ class NotificationUIManager
   // Registrar for the other kind of notifications (event signaling).
   NotificationRegistrar registrar_;
 
+  // Prefs listener for the position preference.
+  IntegerPrefMember position_pref_;
+
   DISALLOW_COPY_AND_ASSIGN(NotificationUIManager);
 };
 
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index 1d21c1f..1aa3c9e 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -34,6 +34,7 @@
 #include "chrome/browser/net/predictor_api.h"
 #include "chrome/browser/net/pref_proxy_config_service.h"
 #include "chrome/browser/net/net_pref_observer.h"
+#include "chrome/browser/notifications/notification_ui_manager.h"
 #include "chrome/browser/notifications/desktop_notification_service.h"
 #include "chrome/browser/page_info_model.h"
 #include "chrome/browser/password_manager/password_manager.h"
@@ -100,6 +101,7 @@ void RegisterLocalState(PrefService* local_state) {
   geolocation::RegisterPrefs(local_state);
   AutoFillManager::RegisterBrowserPrefs(local_state);
   BackgroundPageTracker::RegisterPrefs(local_state);
+  NotificationUIManager::RegisterPrefs(local_state);
 #if defined(OS_CHROMEOS)
   chromeos::UserManager::RegisterPrefs(local_state);
   chromeos::UserCrosSettingsProvider::RegisterPrefs(local_state);
diff --git a/chrome/browser/ui/cocoa/notifications/balloon_controller_unittest.mm b/chrome/browser/ui/cocoa/notifications/balloon_controller_unittest.mm
index a63a327..3b168ef 100644
--- a/chrome/browser/ui/cocoa/notifications/balloon_controller_unittest.mm
+++ b/chrome/browser/ui/cocoa/notifications/balloon_controller_unittest.mm
@@ -34,8 +34,9 @@ class MockBalloonCollection : public BalloonCollection {
   virtual bool RemoveBySourceOrigin(const GURL& origin) { return false; }
   virtual void RemoveAll() {}
   virtual bool HasSpace() const { return true; }
-  virtual void ResizeBalloon(Balloon* balloon, const gfx::Size& size) {};
+  virtual void ResizeBalloon(Balloon* balloon, const gfx::Size& size) {}
   virtual void DisplayChanged() {}
+  virtual void SetPositionPreference(PositionPreference preference) {}
   virtual void OnBalloonClosed(Balloon* source) {};
   virtual const Balloons& GetActiveBalloons() {
     NOTREACHED();