Fully create a Panel before adding it to any panel strip.

This isolates panel creation into one spot, making it easier to refactor down the road when panels will be created differently.

Updated code/tests to watch for Panel closing instead of Browser closing, reducing the code that expects Panel to have a browser where possible.

Moved some constants into panel_constants.h and re-indented file.

BUG=127323
TEST=Updated

Review URL: https://chromiumcodereview.appspot.com/10446026

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@139426 0039d316-1c4b-4281-b951-d872f2087c98

22 files changed, 255 insertions, 278 deletions

diff --git a/chrome/browser/ui/panels/base_panel_browser_test.cc b/chrome/browser/ui/panels/base_panel_browser_test.cc
index 0b04b91..0dd7bfe 100644
--- a/chrome/browser/ui/panels/base_panel_browser_test.cc
+++ b/chrome/browser/ui/panels/base_panel_browser_test.cc
@@ -360,7 +360,7 @@ Panel* BasePanelBrowserTest::CreatePanelWithParams(
       ui::GuessWindowManager() == ui::WM_ICE_WM) {
     last_active_browser_to_restore = BrowserList::GetLastActive();
     EXPECT_TRUE(last_active_browser_to_restore);
-    EXPECT_NE(last_active_browser_to_restore, panel->browser());
+    EXPECT_NE(last_active_browser_to_restore, panel_browser);
   }
 #endif
 
@@ -468,17 +468,18 @@ void BasePanelBrowserTest::SetTestingAreas(const gfx::Rect& primary_screen_area,
       work_area.IsEmpty() ? primary_screen_area : work_area);
 }
 
-void BasePanelBrowserTest::CloseWindowAndWait(Browser* browser) {
-  // Closing a browser window may involve several async tasks. Need to use
+void BasePanelBrowserTest::CloseWindowAndWait(Panel* panel) {
+  // Closing a panel may involve several async tasks. Need to use
   // message pump and wait for the notification.
-  size_t browser_count = BrowserList::size();
+  PanelManager* manager = PanelManager::GetInstance();
+  int panel_count = manager->num_panels();
   ui_test_utils::WindowedNotificationObserver signal(
-      chrome::NOTIFICATION_BROWSER_CLOSED,
-      content::Source<Browser>(browser));
-  browser->CloseWindow();
+      chrome::NOTIFICATION_PANEL_CLOSED,
+      content::Source<Panel>(panel));
+  panel->Close();
   signal.Wait();
-  // Now we have one less browser instance.
-  EXPECT_EQ(browser_count - 1, BrowserList::size());
+  // Now we have one less panel.
+  EXPECT_EQ(panel_count - 1, manager->num_panels());
 
 #if defined(OS_MACOSX)
   // Mac window controllers may be autoreleased, and in the non-test
diff --git a/chrome/browser/ui/panels/base_panel_browser_test.h b/chrome/browser/ui/panels/base_panel_browser_test.h
index 61561f4..f845151 100644
--- a/chrome/browser/ui/panels/base_panel_browser_test.h
+++ b/chrome/browser/ui/panels/base_panel_browser_test.h
@@ -100,7 +100,7 @@ class BasePanelBrowserTest : public InProcessBrowserTest {
   void MoveMouseAndWaitForExpansionStateChange(Panel* panel,
                                                const gfx::Point& position);
   static void MoveMouse(const gfx::Point& position);
-  void CloseWindowAndWait(Browser* browser);
+  void CloseWindowAndWait(Panel* panel);
   static std::string MakePanelName(int index);
 
   // |primary_screen_area| must contain |work_area|. If empty rect is passed
diff --git a/chrome/browser/ui/panels/docked_panel_strip.cc b/chrome/browser/ui/panels/docked_panel_strip.cc
index 55b7ffa..6e48d7b 100644
--- a/chrome/browser/ui/panels/docked_panel_strip.cc
+++ b/chrome/browser/ui/panels/docked_panel_strip.cc
@@ -19,10 +19,6 @@
 #include "content/public/browser/notification_source.h"
 
 namespace {
-// Width to height ratio is used to compute the default width or height
-// when only one value is provided.
-const double kPanelDefaultWidthToHeightRatio = 1.62;  // golden ratio
-
 // Occasionally some system, like Windows, might not bring up or down the bottom
 // bar when the mouse enters or leaves the bottom screen area. This is the
 // maximum time we will wait for the bottom bar visibility change notification.
@@ -46,15 +42,6 @@ const int kNumPanelsToAnimateSimultaneously = 3;
 
 }  // namespace
 
-// static
-// These numbers are semi-arbitrary.
-// Motivation for 'width' is to make main buttons on the titlebar functional.
-// Motivation for height is to allow autosized tightly-wrapped panel with a
-// single line of text - so the height is set to be likely less then a titlebar,
-// to make sure even small content is tightly wrapped.
-const int DockedPanelStrip::kPanelMinWidth = 80;
-const int DockedPanelStrip::kPanelMinHeight = 20;
-
 DockedPanelStrip::DockedPanelStrip(PanelManager* panel_manager)
     : PanelStrip(PanelStrip::DOCKED),
       panel_manager_(panel_manager),
@@ -101,24 +88,32 @@ void DockedPanelStrip::AddPanel(Panel* panel,
   // This method does not handle minimized panels.
   DCHECK_EQ(Panel::EXPANDED, panel->expansion_state());
 
+  DCHECK(panel->initialized());
   DCHECK_NE(this, panel->panel_strip());
   panel->set_panel_strip(this);
 
-  bool known_position = (positioning_mask & KNOWN_POSITION) != 0;
+  bool default_position = (positioning_mask & KNOWN_POSITION) == 0;
   bool update_bounds = (positioning_mask & DO_NOT_UPDATE_BOUNDS) == 0;
 
-  if (!panel->initialized()) {
-    DCHECK(!known_position && update_bounds);
-    InsertNewlyCreatedPanel(panel);
-    ScheduleLayoutRefresh();
-  } else if (known_position) {
-    DCHECK(update_bounds);
-    InsertExistingPanelAtKnownPosition(panel);
-    RefreshLayout();
+  if (default_position) {
+    gfx::Size full_size = panel->full_size();
+    gfx::Point pt = GetDefaultPositionForPanel(full_size);
+    panel->SetPanelBounds(gfx::Rect(pt, full_size));
+    panels_.push_back(panel);
   } else {
-    DCHECK(!known_position);
-    InsertExistingPanelAtDefaultPosition(panel);
-    if (update_bounds)
+    DCHECK(update_bounds);
+    int x = panel->GetBounds().x();
+    Panels::iterator iter = panels_.begin();
+    for (; iter != panels_.end(); ++iter)
+      if (x > (*iter)->GetBounds().x())
+        break;
+    panels_.insert(iter, panel);
+  }
+
+  if (update_bounds) {
+    if ((positioning_mask & DELAY_LAYOUT_REFRESH) != 0)
+      ScheduleLayoutRefresh();
+    else
       RefreshLayout();
   }
 }
@@ -146,72 +141,6 @@ gfx::Point DockedPanelStrip::GetDefaultPositionForPanel(
   return gfx::Point(x, display_area_.bottom() - full_size.height());
 }
 
-void DockedPanelStrip::InsertNewlyCreatedPanel(Panel* panel) {
-  DCHECK(!panel->initialized());
-
-  int max_panel_width = panel_manager_->GetMaxPanelWidth();
-  int max_panel_height = panel_manager_->GetMaxPanelHeight();
-  gfx::Size full_size = panel->full_size();
-  int height = full_size.height();
-  int width = full_size.width();
-
-  // Initialize the newly created panel. Does not bump any panels from strip.
-  // We need to come up with some temporary position and dimensions
-  // for this panel -- they may be changed at RefreshLayout time.
-  if (height == 0 && width == 0 && panel_manager_->auto_sizing_enabled()) {
-    // Auto resizable is enabled only if no initial size is provided.
-    panel->SetAutoResizable(true);
-  } else {
-    if (height == 0)
-      height = width / kPanelDefaultWidthToHeightRatio;
-    if (width == 0)
-      width = height * kPanelDefaultWidthToHeightRatio;
-  }
-
-  // Constrain sizes to limits.
-  if (width < kPanelMinWidth)
-    width = kPanelMinWidth;
-  else if (width > max_panel_width)
-    width = max_panel_width;
-
-  if (height < kPanelMinHeight)
-    height = kPanelMinHeight;
-  else if (height > max_panel_height)
-    height = max_panel_height;
-
-  full_size = gfx::Size(width, height);
-  panel->set_full_size(full_size);
-  gfx::Point pt = GetDefaultPositionForPanel(full_size);
-
-  panel->Initialize(gfx::Rect(pt.x(), pt.y(), width, height));
-
-  panel->SetSizeRange(gfx::Size(kPanelMinWidth, kPanelMinHeight),
-                      gfx::Size(max_panel_width, max_panel_height));
-
-  InsertExistingPanelAtKnownPosition(panel);
-}
-
-void DockedPanelStrip::InsertExistingPanelAtKnownPosition(Panel* panel) {
-  DCHECK(panel->initialized());
-
-  int x = panel->GetBounds().x();
-  Panels::iterator iter = panels_.begin();
-  for (; iter != panels_.end(); ++iter)
-    if (x > (*iter)->GetBounds().x())
-      break;
-  panels_.insert(iter, panel);
-}
-
-void DockedPanelStrip::InsertExistingPanelAtDefaultPosition(Panel* panel) {
-  DCHECK(panel->initialized());
-
-  gfx::Size full_size = panel->full_size();
-  gfx::Point pt = GetDefaultPositionForPanel(full_size);
-  panel->SetPanelBounds(gfx::Rect(pt, full_size));
-
-  panels_.push_back(panel);
-}
-
 int DockedPanelStrip::StartingRightPosition() const {
   return display_area_.right();
 }
@@ -456,7 +385,7 @@ void DockedPanelStrip::AdjustPanelBoundsPerExpansionState(Panel* panel,
 
       break;
     case Panel::MINIMIZED:
-      bounds->set_height(Panel::kMinimizedPanelHeight);
+      bounds->set_height(panel::kMinimizedPanelHeight);
 
       break;
     default:
@@ -888,7 +817,7 @@ int DockedPanelStrip::WidthToDisplayPanelInStrip(bool is_for_active_panel,
                                                  double squeeze_factor,
                                                  int full_width) const {
   return is_for_active_panel ? full_width :
-      std::max(kPanelMinWidth,
+      std::max(panel::kPanelMinWidth,
                static_cast<int>(floor(full_width * squeeze_factor)));
 }
 
diff --git a/chrome/browser/ui/panels/docked_panel_strip.h b/chrome/browser/ui/panels/docked_panel_strip.h
index c83c179..b6bc82a 100644
--- a/chrome/browser/ui/panels/docked_panel_strip.h
+++ b/chrome/browser/ui/panels/docked_panel_strip.h
@@ -87,6 +87,10 @@ class DockedPanelStrip : public PanelStrip,
   // Brings up or down the titlebars for all minimized panels.
   void BringUpOrDownTitlebars(bool bring_up);
 
+  // Compute default bounds for a panel of |full_size| that would be used
+  // when adding the panel to the collection.
+  gfx::Point GetDefaultPositionForPanel(const gfx::Size& full_size) const;
+
   // Returns the bottom position for the panel per its expansion state. If auto-
   // hide bottom bar is present, we want to move the minimized panel to the
   // bottom of the screen, not the bottom of the work area.
@@ -141,12 +145,6 @@ class DockedPanelStrip : public PanelStrip,
       DisplaySettingsProvider::DesktopBarAlignment alignment,
       DisplaySettingsProvider::DesktopBarVisibility visibility) OVERRIDE;
 
-  // Helper methods to put the panel to the collection.
-  gfx::Point GetDefaultPositionForPanel(const gfx::Size& full_size) const;
-  void InsertNewlyCreatedPanel(Panel* panel);
-  void InsertExistingPanelAtKnownPosition(Panel* panel);
-  void InsertExistingPanelAtDefaultPosition(Panel* panel);
-
   // Schedules a layout refresh with a short delay to avoid too much flicker.
   void ScheduleLayoutRefresh();
 
@@ -202,12 +200,6 @@ class DockedPanelStrip : public PanelStrip,
 
   static const int kPanelsHorizontalSpacing = 4;
 
-  // Absolute minimum width and height for panels, including non-client area.
-  // Should only be big enough to accomodate a close button on the reasonably
-  // recognisable titlebar.
-  static const int kPanelMinWidth;
-  static const int kPanelMinHeight;
-
   DISALLOW_COPY_AND_ASSIGN(DockedPanelStrip);
 };
 
diff --git a/chrome/browser/ui/panels/panel.cc b/chrome/browser/ui/panels/panel.cc
index 73e1c30..36b94db 100644
--- a/chrome/browser/ui/panels/panel.cc
+++ b/chrome/browser/ui/panels/panel.cc
@@ -21,13 +21,12 @@
 #include "ui/gfx/rect.h"
 
 using content::RenderViewHost;
-using content::WebContents;
 
-Panel::Panel(Browser* browser, const gfx::Size& requested_size)
-    : browser_(browser),
-      panel_strip_(NULL),
+Panel::Panel(const gfx::Size& min_size, const gfx::Size& max_size)
+    : panel_strip_(NULL),
       initialized_(false),
-      full_size_(requested_size),
+      min_size_(min_size),
+      max_size_(max_size),
       max_size_policy_(DEFAULT_MAX_SIZE),
       auto_resizable_(false),
       always_on_top_(false),
@@ -41,15 +40,16 @@ Panel::~Panel() {
   // Invoked by native panel destructor. Do not access native_panel_ here.
 }
 
-void Panel::Initialize(const gfx::Rect& bounds) {
+void Panel::Initialize(const gfx::Rect& bounds, Browser* browser) {
   DCHECK(!initialized_);
+  DCHECK(!panel_strip_);  // Cannot be added to a strip until fully created.
+  DCHECK_EQ(EXPANDED, expansion_state_);
   DCHECK(!bounds.IsEmpty());
   initialized_ = true;
-  native_panel_ = CreateNativePanel(browser_, this, bounds);
+  full_size_ = bounds.size();
+  native_panel_ = CreateNativePanel(browser, this, bounds);
   panel_browser_window_.reset(
-      new PanelBrowserWindow(browser_, this, native_panel_));
-  if (panel_strip_ != NULL)
-    native_panel_->PreventActivationByOS(panel_strip_->IsPanelMinimized(this));
+      new PanelBrowserWindow(browser, this, native_panel_));
 }
 
 void Panel::OnNativePanelClosed() {
@@ -61,10 +61,18 @@ PanelManager* Panel::manager() const {
   return PanelManager::GetInstance();
 }
 
+Browser* Panel::browser() const {
+  return native_panel_->GetPanelBrowser();
+}
+
 BrowserWindow* Panel::browser_window() const {
   return panel_browser_window_.get();
 }
 
+content::WebContents* Panel::WebContents() const {
+  return native_panel_->GetPanelBrowser()->GetSelectedWebContents();
+}
+
 bool Panel::CanMinimize() const {
   return panel_strip_ && panel_strip_->CanMinimizePanel(this) && !IsMinimized();
 }
@@ -124,7 +132,7 @@ void Panel::SetAutoResizable(bool resizable) {
     return;
 
   auto_resizable_ = resizable;
-  WebContents* web_contents = browser()->GetSelectedWebContents();
+  content::WebContents* web_contents = WebContents();
   if (auto_resizable_) {
     if (web_contents)
       EnableWebContentsAutoResize(web_contents);
@@ -149,7 +157,7 @@ void Panel::SetSizeRange(const gfx::Size& min_size, const gfx::Size& max_size) {
   min_size_ = min_size;
   max_size_ = max_size;
 
-  ConfigureAutoResize(browser()->GetSelectedWebContents());
+  ConfigureAutoResize(WebContents());
 }
 
 void Panel::IncreaseMaxSize(const gfx::Size& desired_panel_size) {
@@ -353,7 +361,7 @@ void Panel::OnWindowResizedByMouse(const gfx::Rect& new_bounds) {
     panel_strip_->OnPanelResizedByMouse(this, new_bounds);
 }
 
-void Panel::EnableWebContentsAutoResize(WebContents* web_contents) {
+void Panel::EnableWebContentsAutoResize(content::WebContents* web_contents) {
   DCHECK(web_contents);
   ConfigureAutoResize(web_contents);
 
@@ -363,14 +371,14 @@ void Panel::EnableWebContentsAutoResize(WebContents* web_contents) {
   registrar_.Add(
       this,
       content::NOTIFICATION_WEB_CONTENTS_SWAPPED,
-      content::Source<WebContents>(web_contents));
+      content::Source<content::WebContents>(web_contents));
 }
 
 void Panel::Observe(int type,
                     const content::NotificationSource& source,
                     const content::NotificationDetails& details) {
   DCHECK_EQ(content::NOTIFICATION_WEB_CONTENTS_SWAPPED, type);
-  ConfigureAutoResize(content::Source<WebContents>(source).ptr());
+  ConfigureAutoResize(content::Source<content::WebContents>(source).ptr());
 }
 
 void Panel::OnActiveStateChanged(bool active) {
@@ -392,7 +400,7 @@ void Panel::OnActiveStateChanged(bool active) {
       content::NotificationService::NoDetails());
 }
 
-void Panel::ConfigureAutoResize(WebContents* web_contents) {
+void Panel::ConfigureAutoResize(content::WebContents* web_contents) {
   if (!auto_resizable_ || !web_contents)
     return;
 
@@ -407,7 +415,7 @@ void Panel::ConfigureAutoResize(WebContents* web_contents) {
 }
 
 void Panel::OnWindowSizeAvailable() {
-  ConfigureAutoResize(browser()->GetSelectedWebContents());
+  ConfigureAutoResize(WebContents());
 }
 
 void Panel::OnTitlebarClicked(panel::ClickModifier modifier) {
diff --git a/chrome/browser/ui/panels/panel.h b/chrome/browser/ui/panels/panel.h
index 65dbc3a..b3b5323 100644
--- a/chrome/browser/ui/panels/panel.h
+++ b/chrome/browser/ui/panels/panel.h
@@ -57,14 +57,15 @@ class Panel : public BaseWindow,
     USE_SYSTEM_ATTENTION = 0x02
   };
 
-  // The panel can be minimized to 4-pixel lines.
-  static const int kMinimizedPanelHeight = 4;
-
   virtual ~Panel();
 
   // Returns the PanelManager associated with this panel.
   PanelManager* manager() const;
 
+  // Returns web contents of the panel, if any. There may be none if web
+  // contents have not been added to the panel yet.
+  content::WebContents* WebContents() const;
+
   void SetExpansionState(ExpansionState new_expansion_state);
 
   bool IsDrawingAttention() const;
@@ -132,8 +133,9 @@ class Panel : public BaseWindow,
   // Asynchronous completion of panel close request.
   void OnNativePanelClosed();
 
-  NativePanel* native_panel() { return native_panel_; }
-  Browser* browser() const { return browser_; }
+  // Legacy accessors.
+  Browser* browser() const;
+  NativePanel* native_panel() const { return native_panel_; }
   BrowserWindow* browser_window() const;
 
   // May be NULL if:
@@ -167,7 +169,7 @@ class Panel : public BaseWindow,
   // Panel must be initialized to be "fully created" and ready for use.
   // Only called by PanelManager.
   bool initialized() const { return initialized_; }
-  void Initialize(const gfx::Rect& bounds);
+  void Initialize(const gfx::Rect& bounds, Browser* browser);
 
   // This is different from BrowserWindow::SetBounds():
   // * SetPanelBounds() is only called by PanelManager to manage its position.
@@ -239,7 +241,6 @@ class Panel : public BaseWindow,
  private:
   friend class PanelManager;
   friend class PanelBrowserTest;
-  FRIEND_TEST_ALL_PREFIXES(PanelBrowserTest, RestoredBounds);
 
   enum MaxSizePolicy {
     // Default maximum size is proportional to the work area.
@@ -249,15 +250,11 @@ class Panel : public BaseWindow,
   };
 
   // Panel can only be created using PanelManager::CreatePanel().
-  // |requested_size| is the desired size for the panel, but actual
-  // size may differ after panel layout.
-  Panel(Browser* browser, const gfx::Size& requested_size);
+  explicit Panel(const gfx::Size& min_size, const gfx::Size& max_size);
 
   // Configures the renderer for auto resize (if auto resize is enabled).
   void ConfigureAutoResize(content::WebContents* web_contents);
 
-  Browser* browser_;  // Weak, owned by native panel.
-
   // A BrowserWindow for the browser to interact with.
   scoped_ptr<PanelBrowserWindow> panel_browser_window_;
 
diff --git a/chrome/browser/ui/panels/panel_browser_frame_view.cc b/chrome/browser/ui/panels/panel_browser_frame_view.cc
index 70be53c..d4164b3 100644
--- a/chrome/browser/ui/panels/panel_browser_frame_view.cc
+++ b/chrome/browser/ui/panels/panel_browser_frame_view.cc
@@ -615,7 +615,7 @@ bool PanelBrowserFrameView::UsingDefaultTheme(PaintState paint_state) const {
     return true;
 
   ThemeService* theme_service = ThemeServiceFactory::GetForProfile(
-      panel_browser_view_->panel()->browser()->profile());
+      panel_browser_view_->browser()->profile());
   return theme_service->UsingDefaultTheme();
 }
 
diff --git a/chrome/browser/ui/panels/panel_browser_view.cc b/chrome/browser/ui/panels/panel_browser_view.cc
index 8a6dc80..99db94d 100644
--- a/chrome/browser/ui/panels/panel_browser_view.cc
+++ b/chrome/browser/ui/panels/panel_browser_view.cc
@@ -105,7 +105,7 @@ void PanelBrowserView::Deactivate() {
 #if defined(OS_WIN) && !defined(USE_AURA)
   gfx::NativeWindow native_window = NULL;
   BrowserWindow* browser_window =
-      panel_->manager()->GetNextBrowserWindowToActivate(panel_.get());
+      panel_->manager()->GetNextBrowserWindowToActivate(GetPanelBrowser());
   if (browser_window)
     native_window = browser_window->GetNativeHandle();
   else
diff --git a/chrome/browser/ui/panels/panel_browser_view_browsertest.cc b/chrome/browser/ui/panels/panel_browser_view_browsertest.cc
index d04512b..37d08d0 100644
--- a/chrome/browser/ui/panels/panel_browser_view_browsertest.cc
+++ b/chrome/browser/ui/panels/panel_browser_view_browsertest.cc
@@ -119,8 +119,8 @@ class PanelBrowserViewTest : public BasePanelBrowserTest {
 
   void ClosePanelAndWaitForNotification(Panel* panel) {
     ui_test_utils::WindowedNotificationObserver signal(
-        chrome::NOTIFICATION_BROWSER_CLOSED,
-        content::Source<Browser>(panel->browser()));
+        chrome::NOTIFICATION_PANEL_CLOSED,
+        content::Source<Panel>(panel));
     panel->Close();
     signal.Wait();
   }
diff --git a/chrome/browser/ui/panels/panel_browser_window.cc b/chrome/browser/ui/panels/panel_browser_window.cc
index 7404d23..e839497 100644
--- a/chrome/browser/ui/panels/panel_browser_window.cc
+++ b/chrome/browser/ui/panels/panel_browser_window.cc
@@ -476,5 +476,3 @@ void PanelBrowserWindow::TabInsertedAt(TabContentsWrapper* contents,
     panel_->EnableWebContentsAutoResize(contents->web_contents());
   }
 }
-
-
diff --git a/chrome/browser/ui/panels/panel_browser_window_cocoa.h b/chrome/browser/ui/panels/panel_browser_window_cocoa.h
index 1d541a7..c51c304 100644
--- a/chrome/browser/ui/panels/panel_browser_window_cocoa.h
+++ b/chrome/browser/ui/panels/panel_browser_window_cocoa.h
@@ -88,7 +88,6 @@ class PanelBrowserWindowCocoa : public NativePanel,
                        const content::NotificationDetails& details) OVERRIDE;
 
   Panel* panel() { return panel_.get(); }
-  Browser* browser() const { return browser_.get(); }
 
   // Callback from PanelWindowControllerCocoa that native window was actually
   // closed. The window may not close right away because of onbeforeunload
diff --git a/chrome/browser/ui/panels/panel_browser_window_cocoa.mm b/chrome/browser/ui/panels/panel_browser_window_cocoa.mm
index b35136b..818e4f5f 100644
--- a/chrome/browser/ui/panels/panel_browser_window_cocoa.mm
+++ b/chrome/browser/ui/panels/panel_browser_window_cocoa.mm
@@ -77,7 +77,7 @@ void PanelBrowserWindowCocoa::ShowPanel() {
   // until we return to the runloop. Therefore any calls to
   // |BrowserList::GetLastActive()| (for example, in bookmark_util), will return
   // the previous browser instead if we don't explicitly set it here.
-  BrowserList::SetLastActive(browser());
+  BrowserList::SetLastActive(GetPanelBrowser());
 
   ShowPanelInactive();
   ActivatePanel();
@@ -261,7 +261,7 @@ bool PanelBrowserWindowCocoa::PreHandlePanelKeyboardEvent(
   if (id == -1)
     return false;
 
-  if (browser()->IsReservedCommandOrKey(id, event)) {
+  if (GetPanelBrowser()->IsReservedCommandOrKey(id, event)) {
       return [BrowserWindowUtils handleKeyboardEvent:event.os_event
                                  inWindow:GetNativePanelHandle()];
   }
@@ -285,7 +285,7 @@ void PanelBrowserWindowCocoa::FullScreenModeChanged(
 }
 
 Browser* PanelBrowserWindowCocoa::GetPanelBrowser() const {
-  return browser();
+  return browser_.get();
 }
 
 void PanelBrowserWindowCocoa::DestroyPanelBrowser() {
diff --git a/chrome/browser/ui/panels/panel_browser_window_cocoa_unittest.mm b/chrome/browser/ui/panels/panel_browser_window_cocoa_unittest.mm
index 5ec48a5..694b49c 100644
--- a/chrome/browser/ui/panels/panel_browser_window_cocoa_unittest.mm
+++ b/chrome/browser/ui/panels/panel_browser_window_cocoa_unittest.mm
@@ -97,18 +97,19 @@ class PanelBrowserWindowCocoaTest : public CocoaProfileTest {
     EXPECT_EQ(NSHeight([[titlebar superview] bounds]), NSMaxY(titlebar_frame));
   }
 
-  void ClosePanelAndWait(Browser* browser) {
-    EXPECT_TRUE(browser);
-    // Closing a browser window may involve several async tasks. Need to use
+  void ClosePanelAndWait(Panel* panel) {
+    EXPECT_TRUE(panel);
+    // Closing a panel may involve several async tasks. Need to use
     // message pump and wait for the notification.
-    size_t browser_count = BrowserList::size();
+    PanelManager* manager = PanelManager::GetInstance();
+    int panel_count = manager->num_panels();
     ui_test_utils::WindowedNotificationObserver signal(
-        chrome::NOTIFICATION_BROWSER_CLOSED,
-        content::Source<Browser>(browser));
-    browser->CloseWindow();
+        chrome::NOTIFICATION_PANEL_CLOSED,
+        content::Source<Panel>(panel));
+    panel->Close();
     signal.Wait();
-    // Now we have one less browser instance.
-    EXPECT_EQ(browser_count - 1, BrowserList::size());
+    // Now we have one less panel.
+    EXPECT_EQ(panel_count - 1, manager->num_panels());
   }
 
   NSMenuItem* CreateMenuItem(NSMenu* menu, int command_id) {
@@ -139,8 +140,7 @@ TEST_F(PanelBrowserWindowCocoaTest, CreateClose) {
   // their NIB has it. The controller's lifetime is the window's lifetime.
   EXPECT_EQ(NO, [[native_window->controller_ window] isReleasedWhenClosed]);
 
-  ASSERT_TRUE(panel->browser());
-  ClosePanelAndWait(panel->browser());
+  ClosePanelAndWait(panel);
   EXPECT_EQ(0, manager->num_panels());
 }
 
@@ -161,15 +161,15 @@ TEST_F(PanelBrowserWindowCocoaTest, AssignedBounds) {
   EXPECT_EQ(bounds2.y(), bounds3.y());
 
   // After panel2 is closed, panel3 should take its place.
-  ClosePanelAndWait(panel2->browser());
+  ClosePanelAndWait(panel2);
   bounds3 = panel3->GetBounds();
   EXPECT_EQ(bounds2, bounds3);
 
   // After panel1 is closed, panel3 should take its place.
-  ClosePanelAndWait(panel1->browser());
+  ClosePanelAndWait(panel1);
   EXPECT_EQ(bounds1, panel3->GetBounds());
 
-  ClosePanelAndWait(panel3->browser());
+  ClosePanelAndWait(panel3);
 }
 
 // Same test as AssignedBounds, but checks actual bounds on native OS windows.
@@ -197,7 +197,7 @@ TEST_F(PanelBrowserWindowCocoaTest, NativeBounds) {
   {
     // After panel2 is closed, panel3 should take its place.
     PanelAnimatedBoundsObserver bounds_observer(panel3);
-    ClosePanelAndWait(panel2->browser());
+    ClosePanelAndWait(panel2);
     bounds_observer.Wait();
     bounds3 = [[native_window3->controller_ window] frame];
     EXPECT_EQ(bounds2.origin.x, bounds3.origin.x);
@@ -209,7 +209,7 @@ TEST_F(PanelBrowserWindowCocoaTest, NativeBounds) {
   {
     // After panel1 is closed, panel3 should take its place.
     PanelAnimatedBoundsObserver bounds_observer(panel3);
-    ClosePanelAndWait(panel1->browser());
+    ClosePanelAndWait(panel1);
     bounds_observer.Wait();
     bounds3 = [[native_window3->controller_ window] frame];
     EXPECT_EQ(bounds1.origin.x, bounds3.origin.x);
@@ -218,7 +218,7 @@ TEST_F(PanelBrowserWindowCocoaTest, NativeBounds) {
     EXPECT_EQ(bounds1.size.height, bounds3.size.height);
   }
 
-  ClosePanelAndWait(panel3->browser());
+  ClosePanelAndWait(panel3);
 }
 
 // Verify the titlebar is being created.
@@ -232,7 +232,7 @@ TEST_F(PanelBrowserWindowCocoaTest, TitlebarViewCreate) {
   EXPECT_TRUE(titlebar);
   EXPECT_EQ(native_window->controller_, [titlebar controller]);
 
-  ClosePanelAndWait(panel->browser());
+  ClosePanelAndWait(panel);
 }
 
 // Verify the sizing of titlebar - should be affixed on top of regular titlebar.
@@ -283,7 +283,7 @@ TEST_F(PanelBrowserWindowCocoaTest, TitlebarViewSizing) {
   EXPECT_NE(newTitleFrame.origin.x, oldTitleFrame.origin.x);
   EXPECT_NE(newIconFrame.origin.x, oldIconFrame.origin.x);
 
-  ClosePanelAndWait(panel->browser());
+  ClosePanelAndWait(panel);
 }
 
 // Verify closing behavior of titlebar close button.
@@ -300,8 +300,8 @@ TEST_F(PanelBrowserWindowCocoaTest, TitlebarViewClose) {
   EXPECT_EQ(1, manager->num_panels());
   // Simulate clicking Close Button and wait until the Panel closes.
   ui_test_utils::WindowedNotificationObserver signal(
-      chrome::NOTIFICATION_BROWSER_CLOSED,
-      content::Source<Browser>(panel->browser()));
+      chrome::NOTIFICATION_PANEL_CLOSED,
+      content::Source<Panel>(panel));
   [titlebar simulateCloseButtonClick];
   signal.Wait();
   EXPECT_EQ(0, manager->num_panels());
@@ -338,7 +338,7 @@ TEST_F(PanelBrowserWindowCocoaTest, MenuItems) {
   EXPECT_FALSE([presentation_menu_item isEnabled]);
   EXPECT_FALSE([sync_menu_item isEnabled]);
 
-  ClosePanelAndWait(panel->browser());
+  ClosePanelAndWait(panel);
 }
 
 TEST_F(PanelBrowserWindowCocoaTest, KeyEvent) {
@@ -357,7 +357,7 @@ TEST_F(PanelBrowserWindowCocoaTest, KeyEvent) {
       static_cast<PanelBrowserWindowCocoa*>(panel->native_panel());
   [BrowserWindowUtils handleKeyboardEvent:event
                       inWindow:[native_window->controller_ window]];
-  ClosePanelAndWait(panel->browser());
+  ClosePanelAndWait(panel);
 }
 
 // Verify that the theme provider is properly plumbed through.
@@ -369,7 +369,7 @@ TEST_F(PanelBrowserWindowCocoaTest, ThemeProvider) {
       static_cast<PanelBrowserWindowCocoa*>(panel->native_panel());
   ASSERT_TRUE(native_window);
   EXPECT_TRUE(NULL != [[native_window->controller_ window] themeProvider]);
-  ClosePanelAndWait(panel->browser());
+  ClosePanelAndWait(panel);
 }
 
 TEST_F(PanelBrowserWindowCocoaTest, SetTitle) {
@@ -384,7 +384,7 @@ TEST_F(PanelBrowserWindowCocoaTest, SetTitle) {
   chrome::testing::NSRunLoopRunAllPending();
   EXPECT_NSEQ(@"Untitled", [[native_window->controller_ window] title]);
   EXPECT_NSNE([[native_window->controller_ window] title], previousTitle);
-  ClosePanelAndWait(panel->browser());
+  ClosePanelAndWait(panel);
 }
 
 TEST_F(PanelBrowserWindowCocoaTest, ActivatePanel) {
@@ -411,6 +411,6 @@ TEST_F(PanelBrowserWindowCocoaTest, ActivatePanel) {
   frontmostWindow = [[NSApp orderedWindows] objectAtIndex:0];
   EXPECT_NSEQ(frontmostWindow, [native_window2->controller_ window]);
 
-  ClosePanelAndWait(panel->browser());
-  ClosePanelAndWait(panel2->browser());
+  ClosePanelAndWait(panel);
+  ClosePanelAndWait(panel2);
 }
diff --git a/chrome/browser/ui/panels/panel_browser_window_gtk.cc b/chrome/browser/ui/panels/panel_browser_window_gtk.cc
index 722f703..ca21de9 100644
--- a/chrome/browser/ui/panels/panel_browser_window_gtk.cc
+++ b/chrome/browser/ui/panels/panel_browser_window_gtk.cc
@@ -233,7 +233,7 @@ void PanelBrowserWindowGtk::SaveWindowPosition() {
 void PanelBrowserWindowGtk::SetGeometryHints() {
   // Set minimum height the window can be set to.
   GdkGeometry hints;
-  hints.min_height = Panel::kMinimizedPanelHeight;
+  hints.min_height = panel::kMinimizedPanelHeight;
   hints.min_width = kMinWindowWidth;
   gtk_window_set_geometry_hints(
       window(), GTK_WIDGET(window()), &hints, GDK_HINT_MIN_SIZE);
@@ -292,7 +292,7 @@ const gfx::Image* PanelBrowserWindowGtk::GetThemeFrameImage() const {
     return GetAttentionBackgroundImage();
 
   GtkThemeService* theme_provider = GtkThemeService::GetFrom(
-      browser()->profile());
+      GetPanelBrowser()->profile());
   if (theme_provider->UsingDefaultTheme()) {
     // We choose to use the window frame theme to paint panels for the default
     // theme. This is because the default tab theme does not work well for the
@@ -399,7 +399,7 @@ void PanelBrowserWindowGtk::ActivatePanel() {
 
 void PanelBrowserWindowGtk::DeactivatePanel() {
   BrowserWindow* browser_window =
-      panel_->manager()->GetNextBrowserWindowToActivate(panel_.get());
+      panel_->manager()->GetNextBrowserWindowToActivate(GetPanelBrowser());
   if (browser_window) {
     browser_window->Activate();
   } else {
diff --git a/chrome/browser/ui/panels/panel_browsertest.cc b/chrome/browser/ui/panels/panel_browsertest.cc
index 9132c6e..0947bc2 100644
--- a/chrome/browser/ui/panels/panel_browsertest.cc
+++ b/chrome/browser/ui/panels/panel_browsertest.cc
@@ -161,10 +161,10 @@ class PanelBrowserTest : public BasePanelBrowserTest {
     // Minimize all panels for next stage in test.
     for (size_t index = 0; index < panels.size(); ++index) {
       panels[index]->Minimize();
-      expected_bounds[index].set_height(Panel::kMinimizedPanelHeight);
+      expected_bounds[index].set_height(panel::kMinimizedPanelHeight);
       expected_bounds[index].set_y(
           test_begin_bounds[index].y() +
-          test_begin_bounds[index].height() - Panel::kMinimizedPanelHeight);
+          test_begin_bounds[index].height() - panel::kMinimizedPanelHeight);
       expected_expansion_states[index] = Panel::MINIMIZED;
       EXPECT_EQ(expected_bounds, GetAllPanelBounds());
       EXPECT_EQ(expected_expansion_states, GetAllPanelExpansionStates());
@@ -347,7 +347,7 @@ IN_PROC_BROWSER_TEST_F(PanelBrowserTest, CreatePanel) {
   EXPECT_EQ(bounds.right(),
             panel_manager->docked_strip()->StartingRightPosition());
 
-  CloseWindowAndWait(panel->browser());
+  CloseWindowAndWait(panel);
 
   EXPECT_EQ(0, panel_manager->num_panels());
 }
@@ -364,16 +364,6 @@ IN_PROC_BROWSER_TEST_F(PanelBrowserTest, CreateBigPanel) {
   panel->Close();
 }
 
-IN_PROC_BROWSER_TEST_F(PanelBrowserTest, FindBar) {
-  Panel* panel = CreatePanelWithBounds("PanelTest", gfx::Rect(0, 0, 400, 400));
-  Browser* browser = panel->browser();
-  // FindBar needs tab contents.
-  CreateTestTabContents(browser);
-  browser->ShowFindBar();
-  ASSERT_TRUE(browser->GetFindBarController()->find_bar()->IsFindBarVisible());
-  panel->Close();
-}
-
 // Flaky: http://crbug.com/105445
 IN_PROC_BROWSER_TEST_F(PanelBrowserTest, DISABLED_AutoResize) {
   PanelManager* panel_manager = PanelManager::GetInstance();
@@ -395,7 +385,7 @@ IN_PROC_BROWSER_TEST_F(PanelBrowserTest, DISABLED_AutoResize) {
       chrome::NOTIFICATION_PANEL_BOUNDS_ANIMATIONS_FINISHED,
       content::Source<Panel>(panel));
   EXPECT_TRUE(ui_test_utils::ExecuteJavaScript(
-      panel->browser()->GetSelectedWebContents()->GetRenderViewHost(),
+      panel->WebContents()->GetRenderViewHost(),
       std::wstring(),
       L"changeSize(50);"));
   enlarge.Wait();
@@ -408,7 +398,7 @@ IN_PROC_BROWSER_TEST_F(PanelBrowserTest, DISABLED_AutoResize) {
       chrome::NOTIFICATION_PANEL_BOUNDS_ANIMATIONS_FINISHED,
       content::Source<Panel>(panel));
   EXPECT_TRUE(ui_test_utils::ExecuteJavaScript(
-      panel->browser()->GetSelectedWebContents()->GetRenderViewHost(),
+      panel->WebContents()->GetRenderViewHost(),
       std::wstring(),
       L"changeSize(-30);"));
   shrink.Wait();
@@ -822,6 +812,7 @@ IN_PROC_BROWSER_TEST_F(PanelBrowserTest, MAYBE_ActivatePanelOrTabbedWindow) {
   Panel* panel1 = CreatePanelWithParams(params1);
   CreatePanelParams params2("Panel2", gfx::Rect(), SHOW_AS_ACTIVE);
   Panel* panel2 = CreatePanelWithParams(params2);
+
   // Need tab contents in order to trigger deactivation upon close.
   CreateTestTabContents(panel2->browser());
 
@@ -839,7 +830,7 @@ IN_PROC_BROWSER_TEST_F(PanelBrowserTest, MAYBE_ActivatePanelOrTabbedWindow) {
   browser()->window()->Activate();
   WaitForPanelActiveState(panel2, SHOW_AS_INACTIVE);
   // Close the main tabbed window. That should move focus back to panel.
-  CloseWindowAndWait(browser());
+  browser()->CloseWindow();
   WaitForPanelActiveState(panel2, SHOW_AS_ACTIVE);
 
   // Activate another panel.
@@ -853,7 +844,7 @@ IN_PROC_BROWSER_TEST_F(PanelBrowserTest, MAYBE_ActivatePanelOrTabbedWindow) {
   WaitForPanelActiveState(panel1, SHOW_AS_INACTIVE);
 
   // Close active panel, focus should move to the remaining one.
-  CloseWindowAndWait(panel2->browser());
+  CloseWindowAndWait(panel2);
   WaitForPanelActiveState(panel1, SHOW_AS_ACTIVE);
   panel1->Close();
 }
@@ -892,7 +883,7 @@ IN_PROC_BROWSER_TEST_F(PanelBrowserTest, MAYBE_ActivateDeactivateBasic) {
 #endif
 
 IN_PROC_BROWSER_TEST_F(PanelBrowserTest, MAYBE_ActivateDeactivateMultiple) {
-  BrowserWindow* tabbed_window = BrowserList::GetLastActive()->window();
+  BrowserWindow* tabbed_window = browser()->window();
 
   // Create 4 panels in the following screen layout:
   //    P3  P2  P1  P0
@@ -1262,7 +1253,11 @@ IN_PROC_BROWSER_TEST_F(PanelBrowserTest,
   Panel* panel2 = CreatePanelWithParams(params);
 
   // Close main tabbed window.
-  CloseWindowAndWait(browser());
+  ui_test_utils::WindowedNotificationObserver signal(
+      chrome::NOTIFICATION_BROWSER_CLOSED,
+      content::Source<Browser>(browser()));
+  browser()->CloseWindow();
+  signal.Wait();
 
   EXPECT_EQ(Panel::EXPANDED, panel1->expansion_state());
   EXPECT_EQ(Panel::EXPANDED, panel2->expansion_state());
@@ -1329,11 +1324,11 @@ IN_PROC_BROWSER_TEST_F(PanelBrowserTest,
   Panel* panel_other = CreatePanel(extension_app_name_other);
 
   ui_test_utils::WindowedNotificationObserver signal(
-      chrome::NOTIFICATION_BROWSER_CLOSED,
-      content::Source<Browser>(panel->browser()));
+      chrome::NOTIFICATION_PANEL_CLOSED,
+      content::Source<Panel>(panel));
   ui_test_utils::WindowedNotificationObserver signal1(
-      chrome::NOTIFICATION_BROWSER_CLOSED,
-      content::Source<Browser>(panel1->browser()));
+      chrome::NOTIFICATION_PANEL_CLOSED,
+      content::Source<Panel>(panel1));
 
   // Send unload notification on the first extension.
   extensions::UnloadedExtensionInfo details(extension,
@@ -1367,7 +1362,7 @@ IN_PROC_BROWSER_TEST_F(PanelBrowserTest, OnBeforeUnloadOnClose) {
       FilePath(FILE_PATH_LITERAL("onbeforeunload.html")));
   Panel* panel = CreatePanelWithParams(params);
   EXPECT_EQ(1, panel_manager->num_panels());
-  WebContents* web_contents = panel->browser()->GetSelectedWebContents();
+  WebContents* web_contents = panel->WebContents();
 
   // Close panel and respond to the onbeforeunload dialog with cancel. This is
   // equivalent to clicking "Stay on this page"
@@ -1391,13 +1386,13 @@ IN_PROC_BROWSER_TEST_F(PanelBrowserTest, OnBeforeUnloadOnClose) {
 
   // Close panel and respond to the onbeforeunload dialog with accept. This is
   // equivalent to clicking "Leave this page".
-  ui_test_utils::WindowedNotificationObserver browser_closed(
-      chrome::NOTIFICATION_BROWSER_CLOSED,
-      content::Source<Browser>(panel->browser()));
+  ui_test_utils::WindowedNotificationObserver signal(
+      chrome::NOTIFICATION_PANEL_CLOSED,
+      content::Source<Panel>(panel));
   panel->Close();
   alert = ui_test_utils::WaitForAppModalDialog();
   alert->native_dialog()->AcceptAppModalDialog();
-  browser_closed.Wait();
+  signal.Wait();
   EXPECT_EQ(0, panel_manager->num_panels());
 }
 
@@ -1445,8 +1440,8 @@ IN_PROC_BROWSER_TEST_F(PanelBrowserTest, DISABLED_CreateWithExistingContents) {
 
   // Swapping tab contents back to the browser should close the panel.
   ui_test_utils::WindowedNotificationObserver signal(
-      chrome::NOTIFICATION_BROWSER_CLOSED,
-      content::Source<Browser>(panel_browser));
+      chrome::NOTIFICATION_PANEL_CLOSED,
+      content::Source<Panel>(panel));
   panel_browser->ConvertPopupToTabbedBrowser();
   signal.Wait();
   EXPECT_EQ(0, PanelManager::GetInstance()->num_panels());
@@ -1503,7 +1498,7 @@ IN_PROC_BROWSER_TEST_F(PanelBrowserTest, TightAutosizeAroundSingleLine) {
       chrome::NOTIFICATION_PANEL_BOUNDS_ANIMATIONS_FINISHED,
       content::Source<Panel>(panel));
   EXPECT_TRUE(ui_test_utils::ExecuteJavaScript(
-      panel->browser()->GetSelectedWebContents()->GetRenderViewHost(),
+      panel->WebContents()->GetRenderViewHost(),
       std::wstring(),
       L"document.body.innerHTML ="
       L"'<nobr>line of text and a <button>Button</button>';"));
@@ -1903,12 +1898,12 @@ IN_PROC_BROWSER_TEST_F(PanelAndNotificationTest, FAILS_NoOverlapping) {
 
   // Closing short panel should move the notification balloon down to the same
   // position when tall panel brings up its titlebar.
-  CloseWindowAndWait(panel1->browser());
+  CloseWindowAndWait(panel1);
   EXPECT_EQ(balloon_bottom_after_tall_panel_titlebar_up,
             GetBalloonBottomPosition(balloon));
 
   // Closing the remaining tall panel should move the notification balloon back
   // to its original position.
-  CloseWindowAndWait(panel2->browser());
+  CloseWindowAndWait(panel2);
   EXPECT_EQ(original_balloon_bottom, GetBalloonBottomPosition(balloon));
 }
diff --git a/chrome/browser/ui/panels/panel_constants.h b/chrome/browser/ui/panels/panel_constants.h
index 040b05e..3a640da 100644
--- a/chrome/browser/ui/panels/panel_constants.h
+++ b/chrome/browser/ui/panels/panel_constants.h
@@ -8,33 +8,47 @@
 
 namespace panel {
 
-  // Different platforms use different modifier keys to change the behavior
-  // of a mouse click. This enum captures the meaning of the modifier rather
-  // than the actual modifier key to generalize across platforms.
-  enum ClickModifier {
-    NO_MODIFIER,
-    APPLY_TO_ALL,  // Apply the click behavior to all panels in the strip.
-  };
-
-  // Edge at which a panel is being resized using the mouse.
-  enum ResizingSides {
-    RESIZE_NONE = 0,
-    RESIZE_TOP,
-    RESIZE_TOP_RIGHT,
-    RESIZE_RIGHT,
-    RESIZE_BOTTOM_RIGHT,
-    RESIZE_BOTTOM,
-    RESIZE_BOTTOM_LEFT,
-    RESIZE_LEFT,
-    RESIZE_TOP_LEFT
-  };
-
-  // Ways a panel can be resized.
-  enum Resizability {
-    NOT_RESIZABLE,
-    RESIZABLE_ALL_SIDES,
-    RESIZABLE_ALL_SIDES_EXCEPT_BOTTOM
-  };
+// Absolute minimum width and height for panels, including non-client area.
+// Should only be big enough to accomodate a close button on the reasonably
+// recognisable titlebar.
+// These numbers are semi-arbitrary.
+// Motivation for 'width' is to make main buttons on the titlebar functional.
+// Motivation for height is to allow autosized tightly-wrapped panel with a
+// single line of text - so the height is set to be likely less then a titlebar,
+// to make sure even small content is tightly wrapped.
+const int kPanelMinWidth = 80;
+const int kPanelMinHeight = 20;
+
+// The panel can be minimized to 4-pixel lines.
+static const int kMinimizedPanelHeight = 4;
+
+// Different platforms use different modifier keys to change the behavior
+// of a mouse click. This enum captures the meaning of the modifier rather
+// than the actual modifier key to generalize across platforms.
+enum ClickModifier {
+  NO_MODIFIER,
+  APPLY_TO_ALL,  // Apply the click behavior to all panels in the strip.
+};
+
+// Edge at which a panel is being resized using the mouse.
+enum ResizingSides {
+  RESIZE_NONE = 0,
+  RESIZE_TOP,
+  RESIZE_TOP_RIGHT,
+  RESIZE_RIGHT,
+  RESIZE_BOTTOM_RIGHT,
+  RESIZE_BOTTOM,
+  RESIZE_BOTTOM_LEFT,
+  RESIZE_LEFT,
+  RESIZE_TOP_LEFT
+};
+
+// Ways a panel can be resized.
+enum Resizability {
+  NOT_RESIZABLE,
+  RESIZABLE_ALL_SIDES,
+  RESIZABLE_ALL_SIDES_EXCEPT_BOTTOM
+};
 
 }  // namespace panel
 
diff --git a/chrome/browser/ui/panels/panel_drag_browsertest.cc b/chrome/browser/ui/panels/panel_drag_browsertest.cc
index 85dff1e..a9b551e1 100644
--- a/chrome/browser/ui/panels/panel_drag_browsertest.cc
+++ b/chrome/browser/ui/panels/panel_drag_browsertest.cc
@@ -541,7 +541,7 @@ IN_PROC_BROWSER_TEST_F(PanelDragBrowserTest, CloseDockedPanelOnDrag) {
     // Closing another panel while dragging in progress will keep the dragging
     // panel intact.
     // We have:  P1*  P4  P3
-    CloseWindowAndWait(panel2->browser());
+    CloseWindowAndWait(panel2);
     EXPECT_TRUE(drag_controller->IsDragging());
     EXPECT_EQ(panel1, drag_controller->dragging_panel());
 
@@ -596,7 +596,7 @@ IN_PROC_BROWSER_TEST_F(PanelDragBrowserTest, CloseDockedPanelOnDrag) {
     // Closing another panel while dragging in progress will keep the dragging
     // panel intact.
     // We have:  P1*  P4
-    CloseWindowAndWait(panel3->browser());
+    CloseWindowAndWait(panel3);
     EXPECT_TRUE(drag_controller->IsDragging());
     EXPECT_EQ(panel1, drag_controller->dragging_panel());
 
@@ -644,7 +644,7 @@ IN_PROC_BROWSER_TEST_F(PanelDragBrowserTest, CloseDockedPanelOnDrag) {
 
     // Closing the dragging panel should end the drag.
     // We have:  P4
-    CloseWindowAndWait(panel1->browser());
+    CloseWindowAndWait(panel1);
     EXPECT_FALSE(drag_controller->IsDragging());
 
     ASSERT_EQ(1, docked_strip->num_panels());
@@ -744,7 +744,7 @@ IN_PROC_BROWSER_TEST_F(PanelDragBrowserTest, CloseDetachedPanelOnDrag) {
 
     // Closing another panel while dragging in progress will keep the dragging
     // panel intact.
-    CloseWindowAndWait(panel2->browser());
+    CloseWindowAndWait(panel2);
     EXPECT_TRUE(drag_controller->IsDragging());
     EXPECT_EQ(panel1, drag_controller->dragging_panel());
 
@@ -791,7 +791,7 @@ IN_PROC_BROWSER_TEST_F(PanelDragBrowserTest, CloseDetachedPanelOnDrag) {
 
     // Closing another panel while dragging in progress will keep the dragging
     // panel intact.
-    CloseWindowAndWait(panel3->browser());
+    CloseWindowAndWait(panel3);
     EXPECT_TRUE(drag_controller->IsDragging());
     EXPECT_EQ(panel1, drag_controller->dragging_panel());
 
@@ -830,7 +830,7 @@ IN_PROC_BROWSER_TEST_F(PanelDragBrowserTest, CloseDetachedPanelOnDrag) {
     EXPECT_EQ(panel4_position, panel4->GetBounds().origin());
 
     // Closing the dragging panel should end the drag.
-    CloseWindowAndWait(panel1->browser());
+    CloseWindowAndWait(panel1);
     EXPECT_FALSE(drag_controller->IsDragging());
 
     ASSERT_EQ(1, detached_strip->num_panels());
diff --git a/chrome/browser/ui/panels/panel_manager.cc b/chrome/browser/ui/panels/panel_manager.cc
index f9b933a..0a3a8e0 100644
--- a/chrome/browser/ui/panels/panel_manager.cc
+++ b/chrome/browser/ui/panels/panel_manager.cc
@@ -43,6 +43,10 @@ const double kPanelMaxWidthFactor = 0.35;
 
 // Maxmium height of a panel is based on a factor of the working area.
 const double kPanelMaxHeightFactor = 0.5;
+
+// Width to height ratio is used to compute the default width or height
+// when only one value is provided.
+const double kPanelDefaultWidthToHeightRatio = 1.62;  // golden ratio
 }  // namespace
 
 // static
@@ -138,13 +142,51 @@ Panel* PanelManager::CreatePanel(Browser* browser) {
   // 2) On windows, display settings notification is tied to a window. When
   //    display settings are changed at the time that no panel exists, we do
   //    not receive any notification.
-  if (num_panels() == 0)
+  if (num_panels() == 0) {
     display_settings_provider_->OnDisplaySettingsChanged();
+    display_settings_provider_->AddFullScreenObserver(this);
+  }
+
+  // Compute initial bounds for the panel.
+  gfx::Size requested_size(browser->override_bounds().size());
+  int width = requested_size.width();
+  int height = requested_size.height();
+  if (width == 0)
+    width = height * kPanelDefaultWidthToHeightRatio;
+  else if (height == 0)
+    height = width / kPanelDefaultWidthToHeightRatio;
+
+  gfx::Size min_size(panel::kPanelMinWidth, panel::kPanelMinHeight);
+  gfx::Size max_size(GetMaxPanelWidth(), GetMaxPanelHeight());
+  if (width < min_size.width())
+    width = min_size.width();
+  else if (width > max_size.width())
+    width = max_size.width();
+
+  if (height < min_size.height())
+    height = min_size.height();
+  else if (height > max_size.height())
+    height = max_size.height();
+
+  gfx::Size panel_size(width, height);
+  gfx::Rect bounds(docked_strip_->GetDefaultPositionForPanel(panel_size),
+                   panel_size);
+
+  // Create the (legacy) panel.
+  Panel* panel = new Panel(min_size, max_size);
+  panel->Initialize(bounds, browser);
+
+  // Auto resizable feature is enabled only if no initial size is requested.
+  if (auto_sizing_enabled() && requested_size.width() == 0 &&
+      requested_size.height() == 0) {
+    panel->SetAutoResizable(true);
+  }
 
-  int width = browser->override_bounds().width();
-  int height = browser->override_bounds().height();
-  Panel* panel = new Panel(browser, gfx::Size(width, height));
-  docked_strip_->AddPanel(panel, PanelStrip::DEFAULT_POSITION);
+  // Add the panel to the docked strip.
+  // Delay layout refreshes in case multiple panels are created within
+  // a short time of one another or the focus changes shortly after panel
+  // is created to avoid excessive screen redraws.
+  docked_strip_->AddPanel(panel, PanelStrip::DELAY_LAYOUT_REFRESH);
   docked_strip_->UpdatePanelOnStripChange(panel);
 
   content::NotificationService::current()->Notify(
@@ -152,10 +194,6 @@ Panel* PanelManager::CreatePanel(Browser* browser) {
       content::Source<Panel>(panel),
       content::NotificationService::NoDetails());
 
-  if (num_panels() == 1) {
-    display_settings_provider_->AddFullScreenObserver(this);
-  }
-
   return panel;
 }
 
@@ -252,13 +290,13 @@ void PanelManager::BringUpOrDownTitlebars(bool bring_up) {
 }
 
 BrowserWindow* PanelManager::GetNextBrowserWindowToActivate(
-    Panel* panel) const {
+    Browser* current_browser) const {
   // Find the last active browser window that is not minimized.
   BrowserList::const_reverse_iterator iter = BrowserList::begin_last_active();
   BrowserList::const_reverse_iterator end = BrowserList::end_last_active();
   for (; (iter != end); ++iter) {
     Browser* browser = *iter;
-    if (panel->browser() != browser && !browser->window()->IsMinimized())
+    if (current_browser != browser && !browser->window()->IsMinimized())
       return browser->window();
   }
 
diff --git a/chrome/browser/ui/panels/panel_manager.h b/chrome/browser/ui/panels/panel_manager.h
index 9eb76dd..4b1f192 100644
--- a/chrome/browser/ui/panels/panel_manager.h
+++ b/chrome/browser/ui/panels/panel_manager.h
@@ -80,7 +80,7 @@ class PanelManager : public DisplaySettingsProvider::DisplayAreaObserver,
   // Returns the next browser window which could be either panel window or
   // tabbed window, to switch to if the given panel is going to be deactivated.
   // Returns NULL if such window cannot be found.
-  BrowserWindow* GetNextBrowserWindowToActivate(Panel* panel) const;
+  BrowserWindow* GetNextBrowserWindowToActivate(Browser* current_browser) const;
 
   int num_panels() const;
   std::vector<Panel*> panels() const;
diff --git a/chrome/browser/ui/panels/panel_resize_browsertest.cc b/chrome/browser/ui/panels/panel_resize_browsertest.cc
index 0b9ea8d..7ca7ea3 100644
--- a/chrome/browser/ui/panels/panel_resize_browsertest.cc
+++ b/chrome/browser/ui/panels/panel_resize_browsertest.cc
@@ -288,7 +288,7 @@ IN_PROC_BROWSER_TEST_F(PanelResizeBrowserTest, CloseDetachedPanelOnResize) {
   panel1_bounds.Offset(-10, 0);
   EXPECT_EQ(panel1_bounds, panel1->GetBounds());
 
-  CloseWindowAndWait(panel2->browser());
+  CloseWindowAndWait(panel2);
   EXPECT_TRUE(resize_controller->IsResizing());
   EXPECT_EQ(2, detached_strip->num_panels());
 
@@ -308,7 +308,7 @@ IN_PROC_BROWSER_TEST_F(PanelResizeBrowserTest, CloseDetachedPanelOnResize) {
                                    panel3_bounds.height() - 12));
   EXPECT_EQ(panel3_bounds, panel3->GetBounds());
 
-  CloseWindowAndWait(panel3->browser());
+  CloseWindowAndWait(panel3);
   EXPECT_EQ(1, detached_strip->num_panels());
   // Since we closed the panel we were resizing, we should be out of the
   // resizing mode by now.
diff --git a/chrome/browser/ui/panels/panel_strip.h b/chrome/browser/ui/panels/panel_strip.h
index 60a1a1b..e18dbb3 100644
--- a/chrome/browser/ui/panels/panel_strip.h
+++ b/chrome/browser/ui/panels/panel_strip.h
@@ -29,8 +29,12 @@ class PanelStrip {
     DEFAULT_POSITION = 0x0,
     // The panel is being added based on its current known position.
     KNOWN_POSITION = 0x1,
-    // Do not update panel bounds. Only valid with DEFAULT_POSITION.
-    DO_NOT_UPDATE_BOUNDS = 0x2
+    // Do not update panel bounds. Only valid with DEFAULT_POSIITON.
+    DO_NOT_UPDATE_BOUNDS = 0x2,
+    // Wait for a brief delay before refreshing layout of the strip after
+    // adding panel to the strip. If not set, the strip will refresh its layout
+    // immediately.
+    DELAY_LAYOUT_REFRESH = 0x4,
   };
 
   Type type() const { return type_; }
diff --git a/chrome/browser/ui/panels/panel_window_controller_cocoa.mm b/chrome/browser/ui/panels/panel_window_controller_cocoa.mm
index 22dfdd6..87a7fb0 100644
--- a/chrome/browser/ui/panels/panel_window_controller_cocoa.mm
+++ b/chrome/browser/ui/panels/panel_window_controller_cocoa.mm
@@ -443,12 +443,13 @@ enum {
 }
 
 - (ui::ThemeProvider*)themeProvider {
-  return ThemeServiceFactory::GetForProfile(windowShim_->browser()->profile());
+  return ThemeServiceFactory::GetForProfile(
+      windowShim_->GetPanelBrowser()->profile());
 }
 
 - (ThemedWindowStyle)themedWindowStyle {
   ThemedWindowStyle style = THEMED_POPUP;
-  if (windowShim_->browser()->profile()->IsOffTheRecord())
+  if (windowShim_->GetPanelBrowser()->profile()->IsOffTheRecord())
     style |= THEMED_INCOGNITO;
   return style;
 }
@@ -547,7 +548,7 @@ enum {
 
 - (void)updateTitleBar {
   NSString* newTitle = base::SysUTF16ToNSString(
-      windowShim_->browser()->GetWindowTitleForCurrentTab());
+      windowShim_->GetPanelBrowser()->GetWindowTitleForCurrentTab());
   pendingWindowTitle_.reset(
       [BrowserWindowUtils scheduleReplaceOldTitle:pendingWindowTitle_.get()
                                      withNewTitle:newTitle
@@ -570,7 +571,7 @@ enum {
                                                   image:iconImage];
   } else {
     NSImage* iconImage = mac::FaviconForTabContents(
-        windowShim_->browser()->GetSelectedTabContentsWrapper());
+        windowShim_->GetPanelBrowser()->GetSelectedTabContentsWrapper());
     if (!iconImage)
       iconImage = gfx::GetCachedImageWithName(@"nav.pdf");
     NSImageView* iconView =
@@ -635,7 +636,8 @@ enum {
   if (action == @selector(commandDispatch:) ||
       action == @selector(commandDispatchUsingKeyModifiers:)) {
     NSInteger tag = [item tag];
-    CommandUpdater* command_updater = windowShim_->browser()->command_updater();
+    CommandUpdater* command_updater =
+        windowShim_->GetPanelBrowser()->command_updater();
     if (command_updater->SupportsCommand(tag)) {
       enable = command_updater->IsCommandEnabled(tag);
       // Disable commands that do not apply to Panels.
@@ -667,7 +669,7 @@ enum {
 // disabled in the UI in validateUserInterfaceItem:.
 - (void)commandDispatch:(id)sender {
   DCHECK(sender);
-  windowShim_->browser()->ExecuteCommand([sender tag]);
+  windowShim_->GetPanelBrowser()->ExecuteCommand([sender tag]);
 }
 
 // Same as |-commandDispatch:|, but executes commands using a disposition
@@ -678,12 +680,12 @@ enum {
   WindowOpenDisposition disposition =
       event_utils::WindowOpenDispositionFromNSEventWithFlags(
           event, [event modifierFlags]);
-  windowShim_->browser()->ExecuteCommandWithDisposition(
+  windowShim_->GetPanelBrowser()->ExecuteCommandWithDisposition(
       [sender tag], disposition);
 }
 
 - (void)executeCommand:(int)command {
-  windowShim_->browser()->ExecuteCommandIfEnabled(command);
+  windowShim_->GetPanelBrowser()->ExecuteCommandIfEnabled(command);
 }
 
 // Handler for the custom Close button.
@@ -714,7 +716,7 @@ enum {
 // finally ready.
 // This callback is only called if the standard Close button is enabled in XIB.
 - (BOOL)windowShouldClose:(id)sender {
-  Browser* browser = windowShim_->browser();
+  Browser* browser = windowShim_->GetPanelBrowser();
   // Give beforeunload handlers the chance to cancel the close before we hide
   // the window below.
   if (!browser->ShouldCloseWindow())
@@ -739,7 +741,7 @@ enum {
 // When windowShouldClose returns YES (or if controller receives direct 'close'
 // signal), window will be unconditionally closed. Clean up.
 - (void)windowWillClose:(NSNotification*)notification {
-  DCHECK(windowShim_->browser()->tab_strip_model()->empty());
+  DCHECK(windowShim_->GetPanelBrowser()->tab_strip_model()->empty());
   // Avoid callbacks from a nonblocking animation in progress, if any.
   [self terminateBoundsAnimation];
   windowShim_->DidCloseNativeWindow();
@@ -899,7 +901,7 @@ enum {
 // whether it's refactoring more things into BrowserWindowUtils or making a
 // common base controller for browser windows.
 - (void)windowDidBecomeKey:(NSNotification*)notification {
-  BrowserList::SetLastActive(windowShim_->browser());
+  BrowserList::SetLastActive(windowShim_->GetPanelBrowser());
 
   // We need to activate the controls (in the "WebView"). To do this, get the
   // selected WebContents's RenderWidgetHostView and tell it to activate.
@@ -936,7 +938,7 @@ enum {
     return;
   BrowserWindow* browser_window =
       windowShim_->panel()->manager()->GetNextBrowserWindowToActivate(
-          windowShim_->panel());
+          windowShim_->GetPanelBrowser());
 
   if (browser_window)
     browser_window->Activate();