Add Mouse hover behavior to Mac Panels when minimized

chrome/browser/ui/panels/panel_browser_window_cocoa.mm

Index: chrome/browser/ui/panels/panel_browser_window_cocoa.mm
diff --git a/chrome/browser/ui/panels/panel_browser_window_cocoa.mm b/chrome/browser/ui/panels/panel_browser_window_cocoa.mm
index c4fe97e2b4146eb575fda9abc2a4389b6a6f1656..4a3bda24669469dcefff85921a42cd4398f5961c 100644
--- a/chrome/browser/ui/panels/panel_browser_window_cocoa.mm
+++ b/chrome/browser/ui/panels/panel_browser_window_cocoa.mm
@@ -10,6 +10,7 @@
 #import "chrome/browser/ui/cocoa/browser_window_utils.h"
 #include "chrome/browser/ui/panels/panel.h"
 #include "chrome/browser/ui/panels/panel_manager.h"
+#include "chrome/browser/ui/panels/panel_mouse_watcher.h"
 #import "chrome/browser/ui/panels/panel_titlebar_view_cocoa.h"
 #import "chrome/browser/ui/panels/panel_window_controller_cocoa.h"
 #include "content/common/native_web_keyboard_event.h"
@@ -58,6 +59,9 @@ PanelBrowserWindowCocoa::PanelBrowserWindowCocoa(Browser* browser,
 }
 
 PanelBrowserWindowCocoa::~PanelBrowserWindowCocoa() {
+  PanelMouseWatcher* watcher = PanelMouseWatcher::GetInstance();
+  if (watcher->IsSubscribed(this))
+    watcher->RemoveSubscriber(this);
 }
 
 bool PanelBrowserWindowCocoa::isClosed() {
@@ -109,12 +113,14 @@ void PanelBrowserWindowCocoa::OnPanelExpansionStateChanged(
   int height;  // New height of the Panel in screen coordinates.
   switch (expansion_state) {
     case Panel::EXPANDED:
+      PanelMouseWatcher::GetInstance()->RemoveSubscriber(this);
       height = restored_height_;
       break;
     case Panel::TITLE_ONLY:
       height = [controller_ titlebarHeightInScreeenCoordinates];
       break;
     case Panel::MINIMIZED:
+      PanelMouseWatcher::GetInstance()->AddSubscriber(this);
       height = 3;  // TODO(dimich) merge with GTK patch which defines it better.

[prasadt, 2011/09/21 16:54:15]

You should be able to just use PanelManager::minimized_panel_height().

[Dmitry Titov, 2011/09/21 20:38:51]

Thanks, done.

       break;
     default:
@@ -133,10 +139,14 @@ void PanelBrowserWindowCocoa::OnPanelExpansionStateChanged(
   SetPanelBounds(bounds);
 }
 
+// Coordinates are in gfx coordinate system (screen, with 0,0 at the top left).
 bool PanelBrowserWindowCocoa::ShouldBringUpPanelTitlebar(int mouse_x,
                                                          int mouse_y) const {
-  NOTIMPLEMENTED();
-  return false;
+  // Trigger TITLE_ONLY expansion state to show the titlebar if the mouse is
+  // under the minimized panel or somewhat above it.

[jennb, 2011/09/21 17:48:19]

Comment should also explain 'why'.

[Dmitry Titov, 2011/09/21 20:38:51]

Removed the comment since the 'space above' is gone.

+  int spaceAbovePanel = 3 * [controller_ titlebarHeightInScreeenCoordinates];

[prasadt, 2011/09/21 16:54:15]

Any reason for different behavior on Mac?

I see couple of issues with this:
1) If user minimizes panels, presumably he's using something in full screen mode
and he many not want panels popping up when he hovers on some control at the
bottom of the app.  This is not far fetched if you consider for example, most
media apps which have controls at the bottom.
2) Some other app taking the space right above the panel may have its own
behavior when you hover and we could be covering whatever that app throws up
with the panel titlebar popping up.
3) Consistency across platforms for panel behavior. This may not be a biggie as
a feature but would be nice as it allows us to test all platforms in a
consistent way.

I'm sure you have some advantages in mind for doing this.  Just offering a few
downsides to weigh that against.

[jennb, 2011/09/21 17:48:19]

#1 is a good point. I know the reason for this extra space is to avoid moving
the mouse into the Mac Dock to peek at minimized panels, but I have to agree
with Prasad's first point.

[Dmitry Titov, 2011/09/21 20:38:51]

I think Prasad has a good point indeed, mostly about users being hunting for
some UI at the bottom of the apps windows. Removed the 'hover space above', will
address interaction with Dock in other ways (as part of auto-hide behavior
perhaps).

+  return bounds_.x() <= mouse_x && mouse_x <= bounds_.right() &&
+      mouse_y >= bounds_.y() - spaceAbovePanel;
 }
 
 void PanelBrowserWindowCocoa::ClosePanel() {
@@ -300,7 +310,7 @@ NativePanelTesting* NativePanelTesting::Create(NativePanel* native_panel) {
 
 // static
 PanelMouseWatcher* NativePanelTesting::GetPanelMouseWatcherInstance() {
-  return NULL;
+  return PanelMouseWatcher::GetInstance();
 }
 
 NativePanelTestingCocoa::NativePanelTestingCocoa(NativePanel* native_panel)
@@ -332,12 +342,13 @@ void NativePanelTestingCocoa::FinishDragTitlebar() {
   [titlebar() finishDragTitlebar];
 }
 
+// TODO(dimich) this method is platform-independent. Reuse it.
 void NativePanelTestingCocoa::SetMousePositionForMinimizeRestore(
     const gfx::Point& hover_point) {
-  NOTIMPLEMENTED();
+  PanelMouseWatcher::GetInstance()->HandleMouseMovement(hover_point);
+  MessageLoopForUI::current()->RunAllPending();
 }
 
 int NativePanelTestingCocoa::TitleOnlyHeight() const {
-  NOTIMPLEMENTED();
-  return -1;
+  return [native_panel_window_->controller_ titlebarHeightInScreeenCoordinates];
 }