Changes the tab close button to a dot, unless you're near the button

or the tab is selected.

I'm not to keen on the mouse near names, if you have better ideas
please say so.

BUG=45743
TEST=none

Review URL: http://codereview.chromium.org/2796006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@49795 0039d316-1c4b-4281-b951-d872f2087c98

11 files changed, 289 insertions, 49 deletions

diff --git a/chrome/browser/views/tabs/base_tab.cc b/chrome/browser/views/tabs/base_tab.cc
index f128abc..04124ed 100644
--- a/chrome/browser/views/tabs/base_tab.cc
+++ b/chrome/browser/views/tabs/base_tab.cc
@@ -20,6 +20,7 @@
 #include "gfx/canvas.h"
 #include "gfx/favicon_size.h"
 #include "gfx/font.h"
+#include "gfx/skbitmap_operations.h"
 #include "grit/app_resources.h"
 #include "grit/generated_resources.h"
 #include "grit/theme_resources.h"
@@ -48,20 +49,36 @@ static SkBitmap* close_button_p = NULL;
 
 static SkBitmap* crashed_fav_icon = NULL;
 
-namespace {
-
 ////////////////////////////////////////////////////////////////////////////////
 // TabCloseButton
 //
 //  This is a Button subclass that causes middle clicks to be forwarded to the
 //  parent View by explicitly not handling them in OnMousePressed.
-class TabCloseButton : public views::ImageButton {
+class BaseTab::TabCloseButton : public views::ImageButton {
  public:
-  explicit TabCloseButton(views::ButtonListener* listener)
-      : views::ImageButton(listener) {
+  TabCloseButton(BaseTab* tab, bool show_mini_dot)
+      : views::ImageButton(tab),
+        tab_(tab),
+        is_mouse_near_(!show_mini_dot),
+        color_(0) {
   }
   virtual ~TabCloseButton() {}
 
+  // Sets the color used to derive the background color.
+  void SetColor(SkColor color) {
+    if (color_ == color)
+      return;
+
+    color_ = color;
+    // This is invoked from Paint, so we don't need to schedule a paint.
+    UpdateBackgroundImage(false);
+  }
+
+  // Invoked when the selected state changes.
+  void SelectedStateChanged() {
+    UpdateBackgroundImage(true);
+  }
+
   virtual bool OnMousePressed(const views::MouseEvent& event) {
     bool handled = ImageButton::OnMousePressed(event);
     // Explicitly mark midle-mouse clicks as non-handled to ensure the tab
@@ -82,12 +99,63 @@ class TabCloseButton : public views::ImageButton {
     GetParent()->OnMouseExited(event);
   }
 
+  virtual void OnMouseNear(const views::MouseEvent& event) {
+    is_mouse_near_ = true;
+    UpdateBackgroundImage(true);
+  }
+
+  virtual void OnMouseExitedNear(const views::MouseEvent& event) {
+    is_mouse_near_ = false;
+    UpdateBackgroundImage(true);
+  }
+
  private:
+  // Returns the image to use for the background.
+  static const SkBitmap& GetBackgroundImage(SkColor color, bool is_mouse_near) {
+    // All tabs share the same color, so we cache the bitmaps.
+    static SkColor cached_color = 0;
+    static SkBitmap* near_image = NULL;
+    static SkBitmap* far_image = NULL;
+    if (!near_image || cached_color != color) {
+      cached_color = color;
+      if (!near_image) {
+        near_image = new SkBitmap();
+        far_image = new SkBitmap();
+      }
+      ResourceBundle& rb = ResourceBundle::GetSharedInstance();
+      *near_image = SkBitmapOperations::CreateButtonBackground(
+          color,
+          *rb.GetBitmapNamed(IDR_TAB_CLOSE),
+          *rb.GetBitmapNamed(IDR_TAB_CLOSE_MASK));
+      *far_image = SkBitmapOperations::CreateButtonBackground(
+          color,
+          *rb.GetBitmapNamed(IDR_TAB_CLOSE),
+          *rb.GetBitmapNamed(IDR_TAB_CLOSE_DOT_MASK));
+    }
+    return is_mouse_near ? *near_image : *far_image;
+  }
+
+  // Should we use the near image?
+  bool use_near_image() const { return is_mouse_near_ || tab_->IsSelected(); }
+
+  // Resets the background image.
+  void UpdateBackgroundImage(bool paint) {
+    set_background_image(GetBackgroundImage(color_, use_near_image()));
+    if (paint)
+      SchedulePaint();
+  }
+
+  BaseTab* tab_;
+
+  // Is the mouse near the close button?
+  bool is_mouse_near_;
+
+  // Color used to derive the background image from.
+  SkColor color_;
+
   DISALLOW_COPY_AND_ASSIGN(TabCloseButton);
 };
 
-}  // namespace
-
 // static
 int BaseTab::close_button_width_ = 0;
 // static
@@ -139,7 +207,7 @@ class BaseTab::FavIconCrashAnimation : public LinearAnimation,
   DISALLOW_COPY_AND_ASSIGN(FavIconCrashAnimation);
 };
 
-BaseTab::BaseTab(TabController* controller)
+BaseTab::BaseTab(TabController* controller, bool show_mini_dot)
     : controller_(controller),
       closing_(false),
       dragging_(false),
@@ -151,7 +219,7 @@ BaseTab::BaseTab(TabController* controller)
   BaseTab::InitResources();
 
   // Add the Close Button.
-  TabCloseButton* close_button = new TabCloseButton(this);
+  TabCloseButton* close_button = new TabCloseButton(this, show_mini_dot);
   close_button_ = close_button;
   close_button->SetImage(views::CustomButton::BS_NORMAL, close_button_n);
   close_button->SetImage(views::CustomButton::BS_HOT, close_button_h);
@@ -228,6 +296,10 @@ void BaseTab::StopPulse() {
   pulse_animation_.reset(NULL);
 }
 
+void BaseTab::SelectedChanged() {
+  close_button_->SelectedStateChanged();
+}
+
 bool BaseTab::IsSelected() const {
   return controller() ? controller()->IsTabSelected(this) : true;
 }
@@ -334,6 +406,14 @@ void BaseTab::AdvanceLoadingAnimation(TabRendererData::NetworkState old_state,
   SchedulePaint();
 }
 
+views::ImageButton* BaseTab::close_button() const {
+  return close_button_;
+}
+
+void BaseTab::SetCloseButtonColor(SkColor color) {
+  close_button_->SetColor(color);
+}
+
 void BaseTab::PaintIcon(gfx::Canvas* canvas, int x, int y) {
   if (base::i18n::IsRTL()) {
     if (!data().favicon.isNull())
diff --git a/chrome/browser/views/tabs/base_tab.h b/chrome/browser/views/tabs/base_tab.h
index e2ac34a..c0c9bde 100644
--- a/chrome/browser/views/tabs/base_tab.h
+++ b/chrome/browser/views/tabs/base_tab.h
@@ -32,7 +32,7 @@ class BaseTab : public AnimationDelegate,
                 public views::ContextMenuController,
                 public views::View {
  public:
-  explicit BaseTab(TabController* controller);
+  BaseTab(TabController* controller, bool show_mini_dot);
   ~BaseTab();
 
   // Sets the data this tabs displays. Invokes DataChanged for subclasses to
@@ -71,6 +71,10 @@ class BaseTab : public AnimationDelegate,
     theme_provider_ = provider;
   }
 
+  // Invoked when the selected state changes. Resets the image of the close
+  // button.
+  void SelectedChanged();
+
   // Returns true if the tab is selected.
   virtual bool IsSelected() const;
 
@@ -104,7 +108,10 @@ class BaseTab : public AnimationDelegate,
     return hover_animation_.get();
   }
 
-  views::ImageButton* close_button() const { return close_button_; }
+  views::ImageButton* close_button() const;
+
+  // Sets the color used to derive the close button images.
+  void SetCloseButtonColor(SkColor color);
 
   // Paints the icon at the specified x-coordinate.
   void PaintIcon(gfx::Canvas* canvas, int x, int y);
@@ -143,6 +150,7 @@ class BaseTab : public AnimationDelegate,
  private:
   // The animation object used to swap the favicon with the sad tab icon.
   class FavIconCrashAnimation;
+  class TabCloseButton;
 
   // Set the temporary offset for the favicon. This is used during the crash
   // animation.
@@ -186,7 +194,7 @@ class BaseTab : public AnimationDelegate,
 
   scoped_refptr<AnimationContainer> animation_container_;
 
-  views::ImageButton* close_button_;
+  TabCloseButton* close_button_;
 
   // The current index of the loading animation.
   int loading_animation_frame_;
diff --git a/chrome/browser/views/tabs/side_tab.cc b/chrome/browser/views/tabs/side_tab.cc
index bad2b4e..c2448d2 100644
--- a/chrome/browser/views/tabs/side_tab.cc
+++ b/chrome/browser/views/tabs/side_tab.cc
@@ -13,7 +13,6 @@
 #include "gfx/path.h"
 #include "gfx/skia_util.h"
 #include "grit/app_resources.h"
-#include "grit/theme_resources.h"
 #include "views/controls/button/image_button.h"
 
 namespace {
@@ -38,11 +37,8 @@ const int kPhantomTabIconAlpha = 100;
 // SideTab, public:
 
 SideTab::SideTab(TabController* controller)
-    : BaseTab(controller) {
-  ResourceBundle& rb = ResourceBundle::GetSharedInstance();
-  close_button()->SetBackground(kTextColor,
-                                rb.GetBitmapNamed(IDR_TAB_CLOSE),
-                                rb.GetBitmapNamed(IDR_TAB_CLOSE_MASK));
+    : BaseTab(controller, false) {
+  SetCloseButtonColor(kTextColor);
 }
 
 SideTab::~SideTab() {
diff --git a/chrome/browser/views/tabs/tab.cc b/chrome/browser/views/tabs/tab.cc
index ec34e42..db4fe0c 100644
--- a/chrome/browser/views/tabs/tab.cc
+++ b/chrome/browser/views/tabs/tab.cc
@@ -23,6 +23,7 @@
 #include "grit/theme_resources.h"
 #include "third_party/skia/include/effects/SkGradientShader.h"
 #include "views/controls/button/image_button.h"
+#include "views/widget/root_view.h"
 #include "views/widget/tooltip_manager.h"
 #include "views/widget/widget.h"
 #include "views/window/non_client_view.h"
@@ -105,7 +106,7 @@ const char Tab::kViewClassName[] = "browser/tabs/Tab";
 // Tab, public:
 
 Tab::Tab(TabController* controller)
-    : BaseTab(controller),
+    : BaseTab(controller, true),
       showing_icon_(false),
       showing_close_button_(false),
       close_button_color_(NULL),
@@ -232,13 +233,7 @@ void Tab::Paint(gfx::Canvas* canvas) {
     PaintIcon(canvas);
 
   // If the close button color has changed, generate a new one.
-  if (!close_button_color_ || title_color != close_button_color_) {
-    close_button_color_ = title_color;
-    ResourceBundle& rb = ResourceBundle::GetSharedInstance();
-    close_button()->SetBackground(close_button_color_,
-        rb.GetBitmapNamed(IDR_TAB_CLOSE),
-        rb.GetBitmapNamed(IDR_TAB_CLOSE_MASK));
-  }
+  SetCloseButtonColor(title_color);
 }
 
 void Tab::Layout() {
@@ -286,6 +281,7 @@ void Tab::Layout() {
 
   // Size the Close button.
   showing_close_button_ = ShouldShowCloseBox();
+  gfx::Insets near_insets;
   if (showing_close_button_) {
     int close_button_top =
         kTopPadding + kCloseButtonVertFuzz +
@@ -295,10 +291,24 @@ void Tab::Layout() {
                               close_button_top, close_button_width(),
                               close_button_height());
     close_button()->SetVisible(true);
+    int avail_width = width() - close_button()->bounds().right();
+    if (avail_width > 0) {
+      View* root = GetRootView();
+      if (root) {  // Root is null when dragging.
+        // Enable mouse near events for the region from the top of the browser
+        // to the bottom of the tab.
+        gfx::Point loc;
+        ConvertPointToView(close_button(), GetRootView(), &loc);
+        near_insets.Set(loc.y(), close_button()->x(),
+                        height() - close_button()->bounds().bottom(),
+                        avail_width);
+      }
+    }
   } else {
     close_button()->SetBounds(0, 0, 0, 0);
     close_button()->SetVisible(false);
   }
+  close_button()->RegisterForMouseNearEvents(near_insets);
 
   int title_left = favicon_bounds_.right() + kFavIconTitleSpacing;
   int title_top = kTopPadding + (content_height - font_height()) / 2;
diff --git a/chrome/browser/views/tabs/tab_strip.cc b/chrome/browser/views/tabs/tab_strip.cc
index 77fb8eb..a1631fd 100644
--- a/chrome/browser/views/tabs/tab_strip.cc
+++ b/chrome/browser/views/tabs/tab_strip.cc
@@ -292,8 +292,13 @@ void TabStrip::SelectTabAt(int old_model_index, int new_model_index) {
   }
 
   if (old_model_index >= 0) {
-    GetTabAtTabDataIndex(ModelIndexToTabIndex(old_model_index))->
-        StopMiniTabTitleAnimation();
+    Tab* tab = GetTabAtTabDataIndex(ModelIndexToTabIndex(old_model_index));
+    tab->StopMiniTabTitleAnimation();
+    tab->SelectedChanged();
+  }
+  if (new_model_index >= 0) {
+    GetTabAtTabDataIndex(
+        ModelIndexToTabIndex(new_model_index))->SelectedChanged();
   }
 }
 
diff --git a/views/controls/button/image_button.h b/views/controls/button/image_button.h
index f65118a..c99c77f 100644
--- a/views/controls/button/image_button.h
+++ b/views/controls/button/image_button.h
@@ -18,6 +18,14 @@ namespace views {
 
 class ImageButton : public CustomButton {
  public:
+  enum HorizontalAlignment { ALIGN_LEFT = 0,
+                             ALIGN_CENTER,
+                             ALIGN_RIGHT, };
+
+  enum VerticalAlignment { ALIGN_TOP = 0,
+                           ALIGN_MIDDLE,
+                           ALIGN_BOTTOM };
+
   explicit ImageButton(ButtonListener* listener);
   virtual ~ImageButton();
 
@@ -29,13 +37,10 @@ class ImageButton : public CustomButton {
                      const SkBitmap* image,
                      const SkBitmap* mask);
 
-  enum HorizontalAlignment { ALIGN_LEFT = 0,
-                             ALIGN_CENTER,
-                             ALIGN_RIGHT, };
-
-  enum VerticalAlignment { ALIGN_TOP = 0,
-                           ALIGN_MIDDLE,
-                           ALIGN_BOTTOM };
+  // Explicitly sets the background image.
+  void set_background_image(const SkBitmap& background) {
+    background_image_ = background;
+  }
 
   // Sets how the image is laid out within the button's bounds.
   void SetImageAlignment(HorizontalAlignment h_align,
diff --git a/views/event.h b/views/event.h
index 6f96a71..91c0a53 100644
--- a/views/event.h
+++ b/views/event.h
@@ -41,6 +41,8 @@ class Event {
                    ET_MOUSE_MOVED,
                    ET_MOUSE_ENTERED,
                    ET_MOUSE_EXITED,
+                   ET_MOUSE_NEAR,
+                   ET_MOUSE_EXITED_NEAR,
                    ET_KEY_PRESSED,
                    ET_KEY_RELEASED,
                    ET_MOUSEWHEEL,
@@ -100,7 +102,9 @@ class Event {
            type_ == ET_MOUSE_MOVED ||
            type_ == ET_MOUSE_ENTERED ||
            type_ == ET_MOUSE_EXITED ||
-           type_ == ET_MOUSEWHEEL;
+           type_ == ET_MOUSEWHEEL ||
+           type_ == ET_MOUSE_NEAR ||
+           type_ == ET_MOUSE_EXITED_NEAR;
   }
 
 #if defined(OS_WIN)
diff --git a/views/view.cc b/views/view.cc
index 012240a..988e76b 100644
--- a/views/view.cc
+++ b/views/view.cc
@@ -132,6 +132,21 @@ void View::SetBounds(const gfx::Rect& bounds) {
   }
 }
 
+void View::RegisterForMouseNearEvents(const gfx::Insets& insets) {
+  RootView* root = GetRootView();
+  if (insets.empty()) {
+    near_insets_.reset(NULL);
+    if (root)
+      root->UnregisterViewForNearNotification(this);
+  } else {
+    near_insets_.reset(
+        new gfx::Insets(insets.top(), insets.left(), insets.bottom(),
+                        insets.right()));
+    if (root)
+      root->RegisterViewForNearNotification(this);
+  }
+}
+
 gfx::Rect View::GetLocalBounds(bool include_border) const {
   if (include_border || !border_.get())
     return gfx::Rect(0, 0, width(), height());
@@ -537,7 +552,7 @@ void View::AddChildView(int index, View* v) {
   UpdateTooltip();
   RootView* root = GetRootView();
   if (root)
-    RegisterChildrenForVisibleBoundsNotification(root, v);
+    RegisterChildrenForRootNotifications(root, v);
 
   if (layout_manager_.get())
     layout_manager_->ViewAdded(this, v);
@@ -609,7 +624,7 @@ void View::DoRemoveChildView(View* a_view,
 
     RootView* root = GetRootView();
     if (root)
-      UnregisterChildrenForVisibleBoundsNotification(root, a_view);
+      UnregisterChildrenForRootNotifications(root, a_view);
     a_view->PropagateRemoveNotifications(this);
     a_view->SetParent(NULL);
 
@@ -1440,24 +1455,26 @@ ThemeProvider* View::GetThemeProvider() const {
 }
 
 // static
-void View::RegisterChildrenForVisibleBoundsNotification(
-    RootView* root, View* view) {
+void View::RegisterChildrenForRootNotifications(RootView* root, View* view) {
   DCHECK(root && view);
   if (view->GetNotifyWhenVisibleBoundsInRootChanges())
     root->RegisterViewForVisibleBoundsNotification(view);
+  if (view->near_insets_.get())
+    root->RegisterViewForNearNotification(view);
   for (int i = 0; i < view->GetChildViewCount(); ++i)
-    RegisterChildrenForVisibleBoundsNotification(root, view->GetChildViewAt(i));
+    RegisterChildrenForRootNotifications(root, view->GetChildViewAt(i));
 }
 
 // static
-void View::UnregisterChildrenForVisibleBoundsNotification(
+void View::UnregisterChildrenForRootNotifications(
     RootView* root, View* view) {
   DCHECK(root && view);
   if (view->GetNotifyWhenVisibleBoundsInRootChanges())
     root->UnregisterViewForVisibleBoundsNotification(view);
+  if (view->near_insets_.get())
+    root->UnregisterViewForNearNotification(view);
   for (int i = 0; i < view->GetChildViewCount(); ++i)
-    UnregisterChildrenForVisibleBoundsNotification(root,
-                                                   view->GetChildViewAt(i));
+    UnregisterChildrenForRootNotifications(root, view->GetChildViewAt(i));
 }
 
 void View::AddDescendantToNotify(View* view) {
diff --git a/views/view.h b/views/view.h
index c0f6f07..a9012a5 100644
--- a/views/view.h
+++ b/views/view.h
@@ -178,6 +178,11 @@ class View : public AcceleratorTarget {
   void SetX(int x) { SetBounds(x, y(), width(), height()); }
   void SetY(int y) { SetBounds(x(), y, width(), height()); }
 
+  // Registers this view for mouse near events (OnMouseNear and
+  // OnMouseExitedNear). Mouse near events are sent for the extended rectangle
+  // defined by the bounds of this view + |insets|.
+  void RegisterForMouseNearEvents(const gfx::Insets& insets);
+
   // Returns the left coordinate of the View, relative to the parent View,
   // which is the value of bounds_.x().
   //
@@ -686,6 +691,18 @@ class View : public AcceleratorTarget {
   // Default implementation does nothing. Override as needed.
   virtual void OnMouseExited(const MouseEvent& event);
 
+  // Sent when the mouse enters the rectangle defined by this views bounds and
+  // the insets passed to RegisterForMouseNearEvents. This is only sent for
+  // views that have explicitly registered for near notification
+  // (RegisterForMouseNearEvents).
+  virtual void OnMouseNear(const MouseEvent& event) {}
+
+  // Sent when the mouse exits the rectangle defined by this views bounds and
+  // the insets passed to RegisterForMouseNearEvents. This is only sent for
+  // views that have explicitly registered for near notification
+  // (RegisterForMouseNearEvents).
+  virtual void OnMouseExitedNear(const MouseEvent& event) {}
+
   // Set the MouseHandler for a drag session.
   //
   // A drag session is a stream of mouse events starting
@@ -1176,11 +1193,11 @@ class View : public AcceleratorTarget {
 
   // Recursively descends through all descendant views,
   // registering/unregistering all views that want visible bounds in root
-  // view notification.
-  static void RegisterChildrenForVisibleBoundsNotification(RootView* root,
-                                                           View* view);
-  static void UnregisterChildrenForVisibleBoundsNotification(RootView* root,
-                                                             View* view);
+  // view notification and/or mouse near events.
+  static void RegisterChildrenForRootNotifications(RootView* root, View* view);
+  static void UnregisterChildrenForRootNotifications(RootView* root,
+                                                     View* view);
+
 
   // Adds/removes view to the list of descendants that are notified any time
   // this views location and possibly size are changed.
@@ -1280,6 +1297,9 @@ class View : public AcceleratorTarget {
   // right-to-left locales for this View.
   bool flip_canvas_on_paint_for_rtl_ui_;
 
+  // Insets passed to RegisterForMouseNearEvents.
+  scoped_ptr<gfx::Insets> near_insets_;
+
   // The default value for how long to wait (in ms) before showing a menu
   // button on hover. This value is used if the OS doesn't supply one.
   static const int kShowFolderDropMenuDelay;
diff --git a/views/widget/root_view.cc b/views/widget/root_view.cc
index 3ea101c..2a6798c 100644
--- a/views/widget/root_view.cc
+++ b/views/widget/root_view.cc
@@ -489,6 +489,33 @@ void RootView::OnMouseMoved(const MouseEvent& e) {
     mouse_move_handler_->OnMouseExited(exited_event);
     SetActiveCursor(NULL);
   }
+
+  if (registered_near_views_.empty())
+    return;
+
+  std::set<View*> near_views;
+  GetViewsRegisteredForNearNotification(e, &near_views);
+
+  MouseEvent exited_near_event(Event::ET_MOUSE_EXITED_NEAR, 0, 0, 0);
+  for (std::set<View*>::const_iterator i = near_views_.begin();
+       i != near_views_.end(); ++i) {
+    if (near_views.find(*i) == near_views.end())
+      (*i)->OnMouseExitedNear(exited_near_event);
+  }
+
+  for (std::set<View*>::const_iterator i = near_views.begin();
+       i != near_views.end(); ++i) {
+    if (near_views_.find(*i) == near_views_.end()) {
+      MouseEvent entered_event(Event::ET_MOUSE_ENTERED,
+                               this,
+                               *i,
+                               e.location(),
+                               0);
+      (*i)->OnMouseNear(entered_event);
+    }
+  }
+
+  near_views_.swap(near_views);
 }
 
 void RootView::ProcessOnMouseExited() {
@@ -497,6 +524,8 @@ void RootView::ProcessOnMouseExited() {
     mouse_move_handler_->OnMouseExited(exited_event);
     mouse_move_handler_ = NULL;
   }
+
+  SendMouseExitedNear();
 }
 
 void RootView::SetMouseHandler(View *new_mh) {
@@ -880,6 +909,14 @@ void RootView::UnregisterViewForVisibleBoundsNotification(View* view) {
   }
 }
 
+void RootView::RegisterViewForNearNotification(View* view) {
+  registered_near_views_.insert(view);
+}
+
+void RootView::UnregisterViewForNearNotification(View* view) {
+  registered_near_views_.erase(view);
+}
+
 void RootView::SetMouseLocationAndFlags(const MouseEvent& e) {
   last_mouse_event_flags_ = e.GetFlags();
   last_mouse_event_x_ = e.x();
@@ -936,4 +973,38 @@ void RootView::SetActiveCursor(gfx::NativeCursor cursor) {
 #endif
 }
 
+void RootView::GetViewsRegisteredForNearNotification(
+    const MouseEvent& e,
+    std::set<View*>* near_views) {
+  const gfx::Point& location = e.location();
+  for (std::set<View*>::const_iterator i = registered_near_views_.begin();
+       i != registered_near_views_.end(); ++i) {
+    View* view = *i;
+    DCHECK(view->near_insets_.get());
+    const gfx::Insets& insets = *view->near_insets_;
+    gfx::Point view_loc(view->x() - insets.left(),
+                        view->y() - insets.top());
+    View::ConvertPointToView(view->GetParent(), this, &view_loc);
+    if (location.x() >= view_loc.x() &&
+        location.y() >= view_loc.y() &&
+        location.x() < view_loc.x() + (view->width() + insets.width()) &&
+        location.y() < view_loc.y() + (view->height() + insets.height())) {
+      near_views->insert(view);
+    }
+  }
+}
+
+void RootView::SendMouseExitedNear() {
+  if (near_views_.empty())
+    return;
+
+  MouseEvent exited_near_event(Event::ET_MOUSE_EXITED_NEAR, 0, 0, 0);
+  for (std::set<View*>::const_iterator i = near_views_.begin();
+       i != near_views_.end(); ++i) {
+    (*i)->OnMouseExitedNear(exited_near_event);
+  }
+
+  near_views_.clear();
+}
+
 }  // namespace views
diff --git a/views/widget/root_view.h b/views/widget/root_view.h
index 05887e1..ba1d5d22 100644
--- a/views/widget/root_view.h
+++ b/views/widget/root_view.h
@@ -5,6 +5,7 @@
 #ifndef VIEWS_WIDGET_ROOT_VIEW_H_
 #define VIEWS_WIDGET_ROOT_VIEW_H_
 
+#include <set>
 #include <string>
 
 #include "base/ref_counted.h"
@@ -217,6 +218,10 @@ class RootView : public View,
   void RegisterViewForVisibleBoundsNotification(View* view);
   void UnregisterViewForVisibleBoundsNotification(View* view);
 
+  // Registers/unregisters the View for mouse near events.
+  void RegisterViewForNearNotification(View* view);
+  void UnregisterViewForNearNotification(View* view);
+
   // Returns the next focusable view or view containing a FocusTraversable (NULL
   // if none was found), starting at the starting_view.
   // check_starting_view, can_go_up and can_go_down controls the traversal of
@@ -258,6 +263,15 @@ class RootView : public View,
   // Sets the current cursor, or resets it to the last one if NULL is provided.
   void SetActiveCursor(gfx::NativeCursor cursor);
 
+  // Returns in |near_views| the set of views registered for mouse near events
+  // that overlap with the location of the specified event.
+  void GetViewsRegisteredForNearNotification(const MouseEvent& e,
+                                             std::set<View*>* near_views);
+
+  // Sends OnMouseExitedNear to the set of views the mouse is near and empties
+  // the set.
+  void SendMouseExitedNear();
+
   // The view currently handing down - drag - up
   View* mouse_pressed_handler_;
 
@@ -330,6 +344,16 @@ class RootView : public View,
   bool is_processing_paint_;
 #endif
 
+  // Set of views registered for mouse near events.
+  // NOTE: because views registered for near mouse events can overlap other
+  // views and extend outside the bounds of themselves and ancestors we store
+  // the registered views here and treat them separately. This is generally ok
+  // as there are a small set of views registered for near notification.
+  std::set<View*> registered_near_views_;
+
+  // Set of views the mouse is currently near.
+  std::set<View*> near_views_;
+
   DISALLOW_COPY_AND_ASSIGN(RootView);
 };