Support detaching/attaching panels via inter-strip drags.

chrome/browser/ui/panels/panel_browser_view.cc

Index: chrome/browser/ui/panels/panel_browser_view.cc
diff --git a/chrome/browser/ui/panels/panel_browser_view.cc b/chrome/browser/ui/panels/panel_browser_view.cc
index b3f6d43ad20c6f61957fb0dcda16fb95f3ca71a5..907b2fde4a33585307054d29af07a4552f7fdc83 100644
--- a/chrome/browser/ui/panels/panel_browser_view.cc
+++ b/chrome/browser/ui/panels/panel_browser_view.cc
@@ -462,11 +462,11 @@ bool PanelBrowserView::OnTitlebarMouseDragged(const gfx::Point& location) {
     old_focused_view_ = GetFocusManager()->GetFocusedView();
     GetFocusManager()->SetFocusedView(GetFrameView());
 
-    panel_->manager()->StartDragging(panel_.get());
+    panel_->manager()->StartDragging(panel_.get(), last_mouse_location);
     mouse_dragging_state_ = DRAGGING_STARTED;
   }
   if (mouse_dragging_state_ == DRAGGING_STARTED)
-    panel_->manager()->Drag(delta_x, delta_y);
+    panel_->manager()->Drag(mouse_location_);
   return true;
 }
 
@@ -528,21 +528,29 @@ bool PanelBrowserView::EndDragging(bool cancelled) {
 }
 
 void PanelBrowserView::SetPanelAppIconVisibility(bool visible) {
+  // The panel should not show app icon in the desktop bar if it is in overflow.
 #if defined(OS_WIN) && !defined(USE_AURA)
   gfx::NativeWindow native_window = GetNativeHandle();
-  ::ShowWindow(native_window, SW_HIDE);
   int style = ::GetWindowLong(native_window, GWL_EXSTYLE);
+  int new_style = style;
   if (visible)
-    style &= (~WS_EX_TOOLWINDOW);
+    new_style &= (~WS_EX_TOOLWINDOW);
   else
-    style |= WS_EX_TOOLWINDOW;
-  ::SetWindowLong(native_window, GWL_EXSTYLE, style);
-  ::ShowWindow(native_window, SW_SHOWNA);
+    new_style |= WS_EX_TOOLWINDOW;
+  if (style != new_style) {
+    ::ShowWindow(native_window, SW_HIDE);
+    ::SetWindowLong(native_window, GWL_EXSTYLE, new_style);
+    ::ShowWindow(native_window, SW_SHOWNA);
+  }
 #else
   NOTIMPLEMENTED();
 #endif
 }
 
+void PanelBrowserView::SetPanelAlwaysOnTop(bool on_top) {
+  GetWidget()->SetAlwaysOnTop(on_top);
+}
+
 // NativePanelTesting implementation.
 class NativePanelTestingWin : public NativePanelTesting {
  public:
@@ -550,9 +558,9 @@ class NativePanelTestingWin : public NativePanelTesting {
 
  private:
   virtual void PressLeftMouseButtonTitlebar(
-      const gfx::Point& point) OVERRIDE;
+      const gfx::Point& mouse_location) OVERRIDE;
   virtual void ReleaseMouseButtonTitlebar() OVERRIDE;
-  virtual void DragTitlebar(int delta_x, int delta_y) OVERRIDE;
+  virtual void DragTitlebar(const gfx::Point& mouse_location) OVERRIDE;
   virtual void CancelDragTitlebar() OVERRIDE;
   virtual void FinishDragTitlebar() OVERRIDE;
   virtual bool VerifyDrawingAttention() const OVERRIDE;
@@ -577,23 +585,28 @@ NativePanelTestingWin::NativePanelTestingWin(
 }
 
 void NativePanelTestingWin::PressLeftMouseButtonTitlebar(
-    const gfx::Point& point) {
-  panel_browser_view_->OnTitlebarMousePressed(point);
+    const gfx::Point& mouse_location) {
+  // Convert from the screen coordinate system to the view's coordinate system
+  // since OnTitlebarMouseDragged takes the point in the latter.
+  gfx::Point mouse_location_in_screen_coordinates = mouse_location;
+  views::View::ConvertPointToView(NULL, panel_browser_view_,
+                                  &mouse_location_in_screen_coordinates);
+  panel_browser_view_->OnTitlebarMousePressed(
+      mouse_location_in_screen_coordinates);
 }
 
 void NativePanelTestingWin::ReleaseMouseButtonTitlebar() {
   panel_browser_view_->OnTitlebarMouseReleased();
 }
 
-void NativePanelTestingWin::DragTitlebar(int delta_x, int delta_y) {
-  gfx::Point new_mouse_location = panel_browser_view_->mouse_location_;
-  new_mouse_location.Offset(delta_x, delta_y);
-
+void NativePanelTestingWin::DragTitlebar(const gfx::Point& mouse_location) {
   // Convert from the screen coordinate system to the view's coordinate system
   // since OnTitlebarMouseDragged takes the point in the latter.
+  gfx::Point mouse_location_in_screen_coordinates = mouse_location;
   views::View::ConvertPointToView(NULL, panel_browser_view_,
-                                  &new_mouse_location);
-  panel_browser_view_->OnTitlebarMouseDragged(new_mouse_location);
+                                  &mouse_location_in_screen_coordinates);
+  panel_browser_view_->OnTitlebarMouseDragged(
+      mouse_location_in_screen_coordinates);
 }
 
 void NativePanelTestingWin::CancelDragTitlebar() {