position the balloons after closing in a way that will keep the next one's close button under your mouse; don't reposition them to the normal place until the mouse has left the balloon collection

BUG=47333
TEST=make notifications of different sizes, try to close them all; the X should remain under your mouse
Review URL: http://codereview.chromium.org/2915003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@52526 0039d316-1c4b-4281-b951-d872f2087c98

9 files changed, 215 insertions, 15 deletions

diff --git a/chrome/browser/cocoa/notifications/balloon_controller.mm b/chrome/browser/cocoa/notifications/balloon_controller.mm
index 01a753c..f50adac 100644
--- a/chrome/browser/cocoa/notifications/balloon_controller.mm
+++ b/chrome/browser/cocoa/notifications/balloon_controller.mm
@@ -94,8 +94,8 @@ const int kRightMargin = 1;
 
 - (void)repositionToBalloon {
   DCHECK(balloon_);
-  int x = balloon_->position().x();
-  int y = balloon_->position().y();
+  int x = balloon_->GetPosition().x();
+  int y = balloon_->GetPosition().y();
   int w = [self desiredTotalWidth];
   int h = [self desiredTotalHeight];
 
diff --git a/chrome/browser/gtk/notifications/balloon_view_gtk.cc b/chrome/browser/gtk/notifications/balloon_view_gtk.cc
index dfea155..754684f 100644
--- a/chrome/browser/gtk/notifications/balloon_view_gtk.cc
+++ b/chrome/browser/gtk/notifications/balloon_view_gtk.cc
@@ -160,8 +160,8 @@ void BalloonViewImpl::RepositionToBalloon() {
   gtk_window_get_position(GTK_WINDOW(frame_container_), &start_x, &start_y);
   gtk_window_get_size(GTK_WINDOW(frame_container_), &start_w, &start_h);
 
-  int end_x = balloon_->position().x();
-  int end_y = balloon_->position().y();
+  int end_x = balloon_->GetPosition().x();
+  int end_y = balloon_->GetPosition().y();
   int end_w = GetDesiredTotalWidth();
   int end_h = GetDesiredTotalHeight();
 
diff --git a/chrome/browser/notifications/balloon.h b/chrome/browser/notifications/balloon.h
index 87440c9..7f3b604 100644
--- a/chrome/browser/notifications/balloon.h
+++ b/chrome/browser/notifications/balloon.h
@@ -57,9 +57,15 @@ class Balloon {
   const Notification& notification() const { return *notification_.get(); }
   Profile* profile() const { return profile_; }
 
-  const gfx::Point& position() const { return position_; }
+  gfx::Point GetPosition() const {
+    return position_.Add(offset_);
+  }
   void SetPosition(const gfx::Point& upper_left, bool reposition);
 
+  const gfx::Point& offset() { return offset_;}
+  void set_offset(const gfx::Point& offset) { offset_ = offset; }
+  void add_offset(const gfx::Point& offset) { offset_ = offset_.Add(offset); }
+
   const gfx::Size& content_size() const { return content_size_; }
   void set_content_size(const gfx::Size& size) { content_size_ = size; }
 
@@ -115,6 +121,10 @@ class Balloon {
   gfx::Point position_;
   gfx::Size content_size_;
 
+  // Temporary offset for balloons that need to be positioned in a non-standard
+  // position for keeping the close buttons under the mouse cursor.
+  gfx::Point offset_;
+
   // Smallest size for this balloon where scrollbars will be shown.
   gfx::Size min_scrollbar_size_;
 
diff --git a/chrome/browser/notifications/balloon_collection.cc b/chrome/browser/notifications/balloon_collection.cc
index 09bfb56d..91311d1 100644
--- a/chrome/browser/notifications/balloon_collection.cc
+++ b/chrome/browser/notifications/balloon_collection.cc
@@ -22,6 +22,10 @@ const double kPercentBalloonFillFactor = 0.7;
 // Allow at least this number of balloons on the screen.
 const int kMinAllowedBalloonCount = 2;
 
+// Delay from the mouse leaving the balloon collection before
+// there is a relayout, in milliseconds.
+const int kRepositionDelay = 300;
+
 }  // namespace
 
 // static
@@ -32,7 +36,12 @@ BalloonCollectionImpl::Layout::Placement
     BalloonCollectionImpl::Layout::placement_ =
         Layout::VERTICALLY_FROM_BOTTOM_RIGHT;
 
-BalloonCollectionImpl::BalloonCollectionImpl() {
+BalloonCollectionImpl::BalloonCollectionImpl()
+#if USE_OFFSETS
+    : ALLOW_THIS_IN_INITIALIZER_LIST(reposition_factory_(this)),
+      added_as_message_loop_observer_(false)
+#endif
+{
 }
 
 BalloonCollectionImpl::~BalloonCollectionImpl() {
@@ -49,6 +58,10 @@ void BalloonCollectionImpl::Add(const Notification& notification,
                                                 layout_.max_balloon_height()));
   new_balloon->SetPosition(layout_.OffScreenLocation(), false);
   new_balloon->Show();
+#if USE_OFFSETS
+  if (balloons_.size() > 0)
+    new_balloon->set_offset(balloons_[balloons_.size() - 1]->offset());
+#endif
 
   balloons_.push_back(new_balloon);
   PositionBalloons(false);
@@ -99,12 +112,38 @@ void BalloonCollectionImpl::DisplayChanged() {
 void BalloonCollectionImpl::OnBalloonClosed(Balloon* source) {
   // We want to free the balloon when finished.
   scoped_ptr<Balloon> closed(source);
-  for (Balloons::iterator it = balloons_.begin(); it != balloons_.end(); ++it) {
+  Balloons::iterator it = balloons_.begin();
+
+#if USE_OFFSETS
+  gfx::Point offset;
+  bool apply_offset = false;
+  while (it != balloons_.end()) {
+    if (*it == source) {
+      it = balloons_.erase(it);
+      if (it != balloons_.end()) {
+        apply_offset = true;
+        offset.set_y((source)->offset().y() - (*it)->offset().y() +
+            (*it)->content_size().height() - source->content_size().height());
+      }
+    } else {
+      if (apply_offset)
+        (*it)->add_offset(offset);
+      ++it;
+    }
+  }
+  // Start listening for UI events so we cancel the offset when the mouse
+  // leaves the balloon area.
+  if (apply_offset)
+    AddMessageLoopObserver();
+#else
+  for (; it != balloons_.end(); ++it) {
     if (*it == source) {
       balloons_.erase(it);
       break;
     }
   }
+#endif
+
   PositionBalloons(true);
 
   // There may be no listener in a unit test.
@@ -115,12 +154,56 @@ void BalloonCollectionImpl::OnBalloonClosed(Balloon* source) {
 void BalloonCollectionImpl::PositionBalloons(bool reposition) {
   gfx::Point origin = layout_.GetLayoutOrigin();
   for (Balloons::iterator it = balloons_.begin(); it != balloons_.end(); ++it) {
-    gfx::Point upper_left = layout_.NextPosition(
-        Layout::ConstrainToSizeLimits((*it)->GetViewSize()), &origin);
+    gfx::Point upper_left = layout_.NextPosition((*it)->GetViewSize(), &origin);
     (*it)->SetPosition(upper_left, reposition);
   }
 }
 
+#if USE_OFFSETS
+void BalloonCollectionImpl::AddMessageLoopObserver() {
+  if (!added_as_message_loop_observer_) {
+    MessageLoopForUI::current()->AddObserver(this);
+    added_as_message_loop_observer_ = true;
+  }
+}
+
+void BalloonCollectionImpl::RemoveMessageLoopObserver() {
+  if (added_as_message_loop_observer_) {
+    MessageLoopForUI::current()->RemoveObserver(this);
+    added_as_message_loop_observer_ = false;
+  }
+}
+
+void BalloonCollectionImpl::CancelOffsets() {
+  reposition_factory_.RevokeAll();
+
+  // Unhook from listening to all UI events.
+  RemoveMessageLoopObserver();
+
+  for (Balloons::iterator it = balloons_.begin(); it != balloons_.end(); ++it)
+    (*it)->set_offset(gfx::Point(0, 0));
+
+  PositionBalloons(true);
+}
+
+void BalloonCollectionImpl::HandleMouseMoveEvent() {
+  if (!IsCursorInBalloonCollection()) {
+    // Mouse has left the region.  Schedule a reposition after
+    // a short delay.
+    if (reposition_factory_.empty()) {
+      MessageLoop::current()->PostDelayedTask(
+          FROM_HERE,
+          reposition_factory_.NewRunnableMethod(
+              &BalloonCollectionImpl::CancelOffsets),
+          kRepositionDelay);
+    }
+  } else {
+    // Mouse moved back into the region.  Cancel the reposition.
+    reposition_factory_.RevokeAll();
+  }
+}
+#endif
+
 BalloonCollectionImpl::Layout::Layout() {
   RefreshSystemMetrics();
 }
diff --git a/chrome/browser/notifications/balloon_collection_impl.h b/chrome/browser/notifications/balloon_collection_impl.h
index cec0476..cb06230 100644
--- a/chrome/browser/notifications/balloon_collection_impl.h
+++ b/chrome/browser/notifications/balloon_collection_impl.h
@@ -10,20 +10,34 @@
 #include <deque>
 
 #include "base/basictypes.h"
+#include "base/message_loop.h"
 #include "chrome/browser/notifications/balloon_collection.h"
 #include "gfx/point.h"
 #include "gfx/rect.h"
 
+// Mac balloons grow from the top down and have close buttons on top, so
+// offsetting is not necessary for easy multiple-closing.  Other platforms grow
+// from the bottom up and have close buttons on top, so it is necessary.
+#if defined(OS_MACOSX)
+#define USE_OFFSETS 0
+#else
+#define USE_OFFSETS 1
+#endif
+
 // A balloon collection represents a set of notification balloons being
 // shown on the screen.  It positions new notifications according to
 // a layout, and monitors for balloons being closed, which it reports
 // up to its parent, the notification UI manager.
-class BalloonCollectionImpl : public BalloonCollection {
+class BalloonCollectionImpl : public BalloonCollection
+#if USE_OFFSETS
+                            , public MessageLoopForUI::Observer
+#endif
+{
  public:
   BalloonCollectionImpl();
   virtual ~BalloonCollectionImpl();
 
-  // BalloonCollectionInterface overrides
+  // BalloonCollection interface.
   virtual void Add(const Notification& notification,
                    Profile* profile);
   virtual bool Remove(const Notification& notification);
@@ -35,6 +49,16 @@ class BalloonCollectionImpl : public BalloonCollection {
     return balloons_;
   }
 
+  // MessageLoopForUI::Observer interface.
+#if defined(OS_WIN)
+  virtual void WillProcessMessage(const MSG& event) {}
+  virtual void DidProcessMessage(const MSG& event);
+#endif
+#if defined(OS_LINUX)
+  virtual void WillProcessEvent(GdkEvent* event) {}
+  virtual void DidProcessEvent(GdkEvent* event);
+#endif
+
  protected:
   // Calculates layout values for the balloons including
   // the scaling, the max/min sizes, and the upper left corner of each.
@@ -121,6 +145,21 @@ class BalloonCollectionImpl : public BalloonCollection {
   static gfx::Rect GetMacWorkArea();
 #endif
 
+#if USE_OFFSETS
+  // Start and stop observing all UI events.
+  void AddMessageLoopObserver();
+  void RemoveMessageLoopObserver();
+
+  // Cancel all offset and reposition the balloons normally.
+  void CancelOffsets();
+
+  // Handles a mouse motion while the balloons are temporarily offset.
+  void HandleMouseMoveEvent();
+
+  // Is the current cursor in the balloon area?
+  bool IsCursorInBalloonCollection() const;
+#endif
+
   // Queue of active balloons.
   typedef std::deque<Balloon*> Balloons;
   Balloons balloons_;
@@ -128,6 +167,14 @@ class BalloonCollectionImpl : public BalloonCollection {
   // The layout parameters for balloons in this collection.
   Layout layout_;
 
+#if USE_OFFSETS
+  // Factory for generating delayed reposition tasks on mouse motion.
+  ScopedRunnableMethodFactory<BalloonCollectionImpl> reposition_factory_;
+
+  // Is the balloon collection currently listening for UI events?
+  bool added_as_message_loop_observer_;
+#endif
+
   DISALLOW_COPY_AND_ASSIGN(BalloonCollectionImpl);
 };
 
diff --git a/chrome/browser/notifications/balloon_collection_linux.cc b/chrome/browser/notifications/balloon_collection_linux.cc
index c82b3c1..a499292 100644
--- a/chrome/browser/notifications/balloon_collection_linux.cc
+++ b/chrome/browser/notifications/balloon_collection_linux.cc
@@ -30,6 +30,38 @@ int BalloonCollectionImpl::Layout::VerticalEdgeMargin() const {
   return 5;
 }
 
+void BalloonCollectionImpl::DidProcessEvent(GdkEvent* event) {
+  switch (event->type) {
+    case GDK_MOTION_NOTIFY:
+    case GDK_LEAVE_NOTIFY:
+      HandleMouseMoveEvent();
+      break;
+    default:
+      break;
+  }
+}
+
+bool BalloonCollectionImpl::IsCursorInBalloonCollection() const {
+  if (balloons_.empty())
+    return false;
+
+  gfx::Point upper_left = balloons_[balloons_.size() - 1]->GetPosition();
+  gfx::Point lower_right = layout_.GetLayoutOrigin();
+
+  gfx::Rect bounds = gfx::Rect(upper_left.x(),
+                               upper_left.y(),
+                               lower_right.x() - upper_left.x(),
+                               lower_right.y() - upper_left.y());
+
+  GdkScreen* screen = gdk_screen_get_default();
+  GdkDisplay* display = gdk_screen_get_display(screen);
+  gint x, y;
+  gdk_display_get_pointer(display, NULL, &x, &y, NULL);
+  gfx::Point cursor(x, y);
+
+  return bounds.Contains(cursor);
+}
+
 // 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 a913f25..b5c2351 100644
--- a/chrome/browser/notifications/balloon_collection_win.cc
+++ b/chrome/browser/notifications/balloon_collection_win.cc
@@ -29,6 +29,34 @@ int BalloonCollectionImpl::Layout::VerticalEdgeMargin() const {
   return 0;
 }
 
+void BalloonCollectionImpl::DidProcessMessage(const MSG& msg) {
+  switch (msg.message) {
+    case WM_MOUSEMOVE:
+    case WM_MOUSELEAVE:
+    case WM_NCMOUSELEAVE:
+      HandleMouseMoveEvent();
+      break;
+  }
+}
+
+bool BalloonCollectionImpl::IsCursorInBalloonCollection() const {
+  if (balloons_.empty())
+    return false;
+
+  gfx::Point upper_left = balloons_[balloons_.size() - 1]->GetPosition();
+  gfx::Point lower_right = layout_.GetLayoutOrigin();
+
+  gfx::Rect bounds = gfx::Rect(upper_left.x(),
+                               upper_left.y(),
+                               lower_right.x() - upper_left.x(),
+                               lower_right.y() - upper_left.y());
+
+  DWORD pos = GetMessagePos();
+  gfx::Point cursor(pos);
+
+  return bounds.Contains(cursor);
+}
+
 // 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 4cbe647..34746d1 100644
--- a/chrome/browser/notifications/desktop_notifications_unittest.cc
+++ b/chrome/browser/notifications/desktop_notifications_unittest.cc
@@ -59,7 +59,7 @@ int MockBalloonCollection::UppermostVerticalPosition() {
   int min = 0;
   std::deque<Balloon*>::iterator iter;
   for (iter = balloons_.begin(); iter != balloons_.end(); ++iter) {
-    int pos = (*iter)->position().y();
+    int pos = (*iter)->GetPosition().y();
     if (iter == balloons_.begin() || pos < min)
       min = pos;
   }
diff --git a/chrome/browser/views/notifications/balloon_view.cc b/chrome/browser/views/notifications/balloon_view.cc
index 68c6570..ec9aa95 100644
--- a/chrome/browser/views/notifications/balloon_view.cc
+++ b/chrome/browser/views/notifications/balloon_view.cc
@@ -186,7 +186,7 @@ void BalloonViewImpl::RepositionToBalloon() {
 
   if (!kAnimateEnabled) {
     frame_container_->SetBounds(
-        gfx::Rect(balloon_->position().x(), balloon_->position().y(),
+        gfx::Rect(balloon_->GetPosition().x(), balloon_->GetPosition().y(),
                   GetTotalWidth(), GetTotalHeight()));
     gfx::Rect contents_rect = GetContentsRectangle();
     html_container_->SetBounds(contents_rect);
@@ -198,7 +198,7 @@ void BalloonViewImpl::RepositionToBalloon() {
   }
 
   anim_frame_end_ = gfx::Rect(
-      balloon_->position().x(), balloon_->position().y(),
+      balloon_->GetPosition().x(), balloon_->GetPosition().y(),
       GetTotalWidth(), GetTotalHeight());
   frame_container_->GetBounds(&anim_frame_start_, false);
   animation_.reset(new SlideAnimation(this));
@@ -274,7 +274,7 @@ void BalloonViewImpl::Show(Balloon* balloon) {
 
   balloon_ = balloon;
 
-  SetBounds(balloon_->position().x(), balloon_->position().y(),
+  SetBounds(balloon_->GetPosition().x(), balloon_->GetPosition().y(),
             GetTotalWidth(), GetTotalHeight());
 
   source_label_ = new views::Label(source_label_text);