Fix handling of minimized panel count

chrome/browser/ui/panels/docked_panel_strip.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/panels/docked_panel_strip.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 94 matching lines @@
     if (panel->expansion_state() == Panel::EXPANDED) {
       expansion_state_to_restore = Panel::EXPANDED;
     } else {
       if (are_titlebars_up_ || panel->IsDrawingAttention()) {
         expansion_state_to_restore = Panel::TITLE_ONLY;
         height = panel->TitleOnlyHeight();
       } else {
         expansion_state_to_restore = Panel::MINIMIZED;
         height = Panel::kMinimizedPanelHeight;
       }
-      IncrementMinimizedPanels();
     }
     int y =
         GetBottomPositionForExpansionState(expansion_state_to_restore) - height;
     panel->SetPanelBounds(gfx::Rect(x, y, width, height));
 
     // Update the minimized state to reflect current titlebar mode.
     // Do this AFTER setting panel bounds to avoid an extra bounds change.
     if (panel->expansion_state() != Panel::EXPANDED)
       panel->SetExpansionState(expansion_state_to_restore);
 
@@ skipping 40 matching lines @@
     panel->Initialize(gfx::Rect(x, y, width, height));
   }
 
   // Set panel properties for this strip.
   panel->SetAppIconVisibility(true);
 
   if (panel->has_temporary_layout())
     panels_in_temporary_layout_.insert(panel);
   else
     panels_.push_back(panel);
+
+  UpdateMinimizedPanelCount();
 }
 
 int DockedPanelStrip::GetMaxPanelWidth() const {
   return static_cast<int>(display_area_.width() * kPanelMaxWidthFactor);
 }
 
 int DockedPanelStrip::GetMaxPanelHeight() const {
   return display_area_.height();
 }
 
 int DockedPanelStrip::StartingRightPosition() const {
   return display_area_.right();
 }
 
 int DockedPanelStrip::GetRightMostAvailablePosition() const {
   return panels_.empty() ? StartingRightPosition() :
       (panels_.back()->GetBounds().x() - kPanelsHorizontalSpacing);
 }
 
 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;
   }
 
   // Removing an element from the list will invalidate the iterator that refers
   // to it. We need to update the iterator in that case.
   DCHECK(dragging_panel_current_iterator_ == panels_.end() ||
          *dragging_panel_current_iterator_ != panel);
   bool update_iterator_after_erase =
@@ skipping 10 matching lines @@
     // Just check if other panels can now fit in the freed up space.
     panel_manager_->MovePanelsOutOfOverflowIfCanFit();
   } else {
     Panels::iterator iter = find(panels_.begin(), panels_.end(), panel);
     DCHECK(iter != panels_.end());
     iter = panels_.erase(iter);
     if (update_iterator_after_erase)
       dragging_panel_original_iterator_ = iter;
     RefreshLayout();
   }
+
+  if (panel->expansion_state() != Panel::EXPANDED)
+    UpdateMinimizedPanelCount();
+
 }
 
 bool DockedPanelStrip::CanShowPanelAsActive(const Panel* panel) const {
   // Panels with temporary layout cannot be shown as active.
   return !panel->has_temporary_layout();
 }
 
 bool DockedPanelStrip::CanDragPanel(const Panel* panel) const {
   // Only the panels having temporary layout can't be dragged.
   return !panel->has_temporary_layout();
@@ skipping 115 matching lines @@
 
   dragging_panel_current_iterator_ = dragging_panel_original_iterator_ =
       panels_.end();
 
   RefreshLayout();
 }
 
 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();
   panel->SetPanelBounds(
       gfx::Rect(bounds.right() - size.width(),
                 bottom - size.height(),
                 size.width(),
                 size.height()));
 }
 
@@ skipping 30 matching lines @@
 
 void DockedPanelStrip::RestorePanel(Panel* panel) {
   DCHECK_EQ(this, panel->panel_strip());
   panel->SetExpansionState(Panel::EXPANDED);
 }
 
 bool DockedPanelStrip::IsPanelMinimized(const Panel* panel) const {
   return panel->expansion_state() != Panel::EXPANDED;
 }
 
-void DockedPanelStrip::IncrementMinimizedPanels() {
-  minimized_panel_count_++;
-  if (minimized_panel_count_ == 1)
+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_++;
+  }
+
+  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::DecrementMinimizedPanels() {
-  minimized_panel_count_--;
-  DCHECK_GE(minimized_panel_count_, 0);
-  if (minimized_panel_count_ == 0)
-    panel_manager_->mouse_watcher()->RemoveObserver(this);
-}
-
 void DockedPanelStrip::ResizePanelWindow(
     Panel* panel,
     const gfx::Size& preferred_window_size) {
   // The panel width:
   // * cannot grow or shrink to go beyond [min_width, max_width]
   int new_width = preferred_window_size.width();
   if (new_width > panel->max_size().width())
     new_width = panel->max_size().width();
   if (new_width < panel->min_size().width())
     new_width = panel->min_size().width();
@@ skipping 277 matching lines @@
   DCHECK(panels_in_temporary_layout_.empty());
 
   // Make a copy of the iterator as closing panels can modify the vector.
   Panels panels_copy = panels_;
 
   // Start from the bottom to avoid reshuffling.
   for (Panels::reverse_iterator iter = panels_copy.rbegin();
        iter != panels_copy.rend(); ++iter)
     (*iter)->Close();
 }