Allow panels to be created as detached panels.

chrome/browser/ui/panels/detached_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/detached_panel_strip.h"
 
 #include <algorithm>
 #include "base/logging.h"
 #include "chrome/browser/ui/panels/panel_drag_controller.h"
 #include "chrome/browser/ui/panels/panel_manager.h"
 
+namespace {
+// How much horizontal and vertical offset there is between newly opened
+// detached panels.
+const int kPanelTilePixels = 10;
+}  // namespace
+
 DetachedPanelStrip::DetachedPanelStrip(PanelManager* panel_manager)
     : PanelStrip(PanelStrip::DETACHED),
       panel_manager_(panel_manager) {
 }
 
 DetachedPanelStrip::~DetachedPanelStrip() {
   DCHECK(panels_.empty());
 }
 
 gfx::Rect DetachedPanelStrip::GetDisplayArea() const  {
@@ skipping 37 matching lines @@
   // Nothing needds to be done here: detached panels always stay
   // where the user dragged them.
 }
 
 void DetachedPanelStrip::AddPanel(Panel* panel,
                                   PositioningMask positioning_mask) {
   // positioning_mask is ignored since the detached panel is free-floating.
   DCHECK_NE(this, panel->panel_strip());
   panel->set_panel_strip(this);
   panels_.insert(panel);
+
+  // Offset the default position of the next detached panel if the current
+  // default position is used.
+  if (panel->GetBounds().origin() == default_panel_origin_)
+    default_panel_origin_.Offset(kPanelTilePixels, kPanelTilePixels);

[jianli, 2012/09/04 21:58:47]

What if next default panel origin is out of screen when too many detached panels
are created?

[jennb, 2012/09/04 23:02:44]

Will modify to "wrap-around". Detached panel bounds are also adjusted to fit on
screen when a panel is created. 

 }
 
 void DetachedPanelStrip::RemovePanel(Panel* panel) {
   DCHECK_EQ(this, panel->panel_strip());
   panel->set_panel_strip(NULL);
   panels_.erase(panel);
 }
 
 void DetachedPanelStrip::CloseAll() {
   // Make a copy as closing panels can modify the iterator.
@@ skipping 142 matching lines @@
       static_cast<Panel::AttentionMode>(Panel::USE_PANEL_ATTENTION |
                                         Panel::USE_SYSTEM_ATTENTION));
   panel->SetAlwaysOnTop(false);
   panel->EnableResizeByMouse(true);
   panel->UpdateMinimizeRestoreButtonVisibility();
 }
 
 void DetachedPanelStrip::OnPanelActiveStateChanged(Panel* panel) {
 }
 
+const gfx::Point& DetachedPanelStrip::GetDefaultPanelOrigin() {
+  if (!default_panel_origin_.x() && !default_panel_origin_.y()) {
+    gfx::Rect display_area =
+        panel_manager_->display_settings_provider()->GetDisplayArea();
+    default_panel_origin_.SetPoint(kPanelTilePixels + display_area.x(),
+                                   kPanelTilePixels + display_area.y());
+  }
+  return default_panel_origin_;
+}