Fix bug where panels sometimes don't align on bottom.

chrome/browser/ui/panels/panel_browser_window_gtk.cc

 // Copyright (c) 2011 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/panel_browser_window_gtk.h"
 
 #include "base/bind.h"
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/browser/ui/panels/panel.h"
 #include "chrome/browser/ui/panels/panel_manager.h"
@@ skipping 129 matching lines @@
   BrowserWindowGtk::OnSizeChanged(width, height);
 
   if (window_size_known_)
     return;
 
   window_size_known_ = true;
   int top = bounds_.bottom() - height;
   int left = bounds_.right() - width;
 
   gtk_window_move(window_, left, top);
-  StartBoundsAnimation(bounds_, gfx::Rect(left, top, width, height));
+  StartBoundsAnimation(gfx::Rect(left, top, width, height), bounds_);
   panel_->OnWindowSizeAvailable();
 
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_PANEL_WINDOW_SIZE_KNOWN,
       content::Source<Panel>(panel_.get()),
       content::NotificationService::NoDetails());
 }
 
 bool PanelBrowserWindowGtk::UseCustomFrame() {
   // We always use custom frame for panels.
@@ skipping 254 matching lines @@
   return gfx::Size(window_size.width() - frame.width(),
                    window_size.height() - frame.height());
 }
 
 int PanelBrowserWindowGtk::TitleOnlyHeight() const {
   return titlebar_widget()->allocation.height;
 }
 
 void PanelBrowserWindowGtk::StartBoundsAnimation(
     const gfx::Rect& from_bounds, const gfx::Rect& to_bounds) {
-  animation_start_bounds_ = from_bounds;
+  if (bounds_animator_.get() && bounds_animator_->is_animating()) {
+    animation_start_bounds_ = last_animation_progressed_bounds_;
+  } else {
+    animation_start_bounds_ = from_bounds;
+  }
 
   bounds_animator_.reset(new PanelSlideAnimation(
       this, panel_.get(), from_bounds, to_bounds));
+
   bounds_animator_->Show();
+  last_animation_progressed_bounds_ = animation_start_bounds_;
 }
 
 bool PanelBrowserWindowGtk::IsAnimatingBounds() const {
   return bounds_animator_.get() && bounds_animator_->is_animating();
 }
 
 void PanelBrowserWindowGtk::WillProcessEvent(GdkEvent* event) {
   // Nothing to do.
 }
 
@@ skipping 59 matching lines @@
   //   - Say you minimize the window to 100x3 and move it to 900,997 to keep it
   //     anchored to the bottom.
   //   - resize is an async operation and the window manager will decide that
   //     the move will take the window off screen and it won't honor the
   //     request.
   //   - When resize finally happens, you'll have a 100x3 window a x,y=900,900.
   bool move = (animation_start_bounds_.bottom() != bounds_.bottom()) ||
               (animation_start_bounds_.right() != bounds_.right());
   if (move)
     gtk_window_move(window_, new_bounds.x(), new_bounds.y());
+
+  last_animation_progressed_bounds_ = new_bounds;
 }
 
 void PanelBrowserWindowGtk::CreateDragWidget() {
   DCHECK(!drag_widget_);
   drag_widget_ = gtk_invisible_new();
   g_signal_connect_after(drag_widget_, "drag-begin",
                          G_CALLBACK(OnDragBeginThunk), this);
   g_signal_connect(drag_widget_, "drag-failed",
                    G_CALLBACK(OnDragFailedThunk), this);
   g_signal_connect(drag_widget_, "button-release-event",
@@ skipping 242 matching lines @@
   }
 }
 
 bool NativePanelTestingGtk::IsWindowSizeKnown() const {
   return panel_browser_window_gtk_->window_size_known_;
 }
 
 bool NativePanelTestingGtk::IsAnimatingBounds() const {
   return panel_browser_window_gtk_->IsAnimatingBounds();
 }