Fix handling of minimized panel count

chrome/browser/ui/panels/docked_panel_strip.cc

Index: chrome/browser/ui/panels/docked_panel_strip.cc
diff --git a/chrome/browser/ui/panels/docked_panel_strip.cc b/chrome/browser/ui/panels/docked_panel_strip.cc
index 57a4bee3e475b948b5a596f5f03c7b7d04b30bc8..ce073f3f6fcfed0667a67cf9f07604f34ad73a2f 100644
--- a/chrome/browser/ui/panels/docked_panel_strip.cc
+++ b/chrome/browser/ui/panels/docked_panel_strip.cc
@@ -112,7 +112,6 @@ void DockedPanelStrip::AddPanel(Panel* panel) {
         expansion_state_to_restore = Panel::MINIMIZED;
         height = Panel::kMinimizedPanelHeight;
       }
-      IncrementMinimizedPanels();
     }
     int y =
         GetBottomPositionForExpansionState(expansion_state_to_restore) - height;
@@ -173,6 +172,8 @@ void DockedPanelStrip::AddPanel(Panel* panel) {
     panels_in_temporary_layout_.insert(panel);
   else
     panels_.push_back(panel);
+
+  UpdateMinimizedPanelCount();
 }
 
 int DockedPanelStrip::GetMaxPanelWidth() const {
@@ -196,9 +197,6 @@ void DockedPanelStrip::RemovePanel(Panel* panel) {
   DCHECK_EQ(this, panel->panel_strip());
   panel->set_panel_strip(NULL);
 
-  if (panel->expansion_state() != Panel::EXPANDED)
-    DecrementMinimizedPanels();
-
   if (panel->has_temporary_layout()) {
     panels_in_temporary_layout_.erase(panel);
     return;
@@ -229,6 +227,10 @@ void DockedPanelStrip::RemovePanel(Panel* panel) {
       dragging_panel_original_iterator_ = iter;
     RefreshLayout();
   }
+
+  if (panel->expansion_state() != Panel::EXPANDED)
+    UpdateMinimizedPanelCount();
+
 }
 
 bool DockedPanelStrip::CanShowPanelAsActive(const Panel* panel) const {
@@ -364,26 +366,20 @@ void DockedPanelStrip::EndDraggingPanel(Panel* panel, bool cancelled) {
 void DockedPanelStrip::OnPanelExpansionStateChanged(Panel* panel) {
   gfx::Size size = panel->restored_size();
   Panel::ExpansionState expansion_state = panel->expansion_state();
-  Panel::ExpansionState old_state = panel->old_expansion_state();
   switch (expansion_state) {
     case Panel::EXPANDED:
-      if (old_state == Panel::TITLE_ONLY || old_state == Panel::MINIMIZED)
-        DecrementMinimizedPanels();
       break;
     case Panel::TITLE_ONLY:
       size.set_height(panel->TitleOnlyHeight());
-      if (old_state == Panel::EXPANDED)
-        IncrementMinimizedPanels();
       break;
     case Panel::MINIMIZED:
       size.set_height(Panel::kMinimizedPanelHeight);
-      if (old_state == Panel::EXPANDED)
-        IncrementMinimizedPanels();
       break;
     default:
       NOTREACHED();
       break;
   }
+  UpdateMinimizedPanelCount();
 
   int bottom = GetBottomPositionForExpansionState(expansion_state);
   gfx::Rect bounds = panel->GetBounds();
@@ -434,18 +430,21 @@ bool DockedPanelStrip::IsPanelMinimized(const Panel* panel) const {
   return panel->expansion_state() != Panel::EXPANDED;
 }
 
-void DockedPanelStrip::IncrementMinimizedPanels() {
-  minimized_panel_count_++;
-  if (minimized_panel_count_ == 1)
-    panel_manager_->mouse_watcher()->AddObserver(this);
-  DCHECK_LE(minimized_panel_count_, num_panels());
-}
+void DockedPanelStrip::UpdateMinimizedPanelCount() {

[jennb, 2012/03/12 18:26:27]

Way more efficient to incr/decr a count than re-counting all panels. Is there a
way to ensure accuracy without losing efficiency?

+  int prev_minimized_panel_count = minimized_panel_count_;
+  minimized_panel_count_ = 0;
+  for (Panels::const_iterator i_panel = panels_.begin();

[jianli, 2012/03/12 18:08:56]

nit: normally we use iter or panel_iter.

+       i_panel != panels_.end(); ++i_panel) {
+    if ((*i_panel)->expansion_state() != Panel::EXPANDED)
+      minimized_panel_count_++;
+  }
 
-void DockedPanelStrip::DecrementMinimizedPanels() {
-  minimized_panel_count_--;
-  DCHECK_GE(minimized_panel_count_, 0);
-  if (minimized_panel_count_ == 0)
+  if (prev_minimized_panel_count == 0 && minimized_panel_count_ > 0)
+    panel_manager_->mouse_watcher()->AddObserver(this);
+  if (prev_minimized_panel_count > 0 &&  minimized_panel_count_ == 0)
     panel_manager_->mouse_watcher()->RemoveObserver(this);
+
+  DCHECK_LE(minimized_panel_count_, num_panels());
 }
 
 void DockedPanelStrip::ResizePanelWindow(