Fixes bug in MultiWindowResizeController where it wasn't removing

ash/wm/workspace/multi_window_resize_controller.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 "ash/wm/workspace/multi_window_resize_controller.h"
 
 #include "ash/screen_ash.h"
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/wm/window_animations.h"
@@ skipping 381 matching lines @@
 void MultiWindowResizeController::StartResize(
     const gfx::Point& location_in_screen) {
   DCHECK(!window_resizer_.get());
   DCHECK(windows_.is_valid());
   hide_timer_.Stop();
   gfx::Point location_in_parent(location_in_screen);
   aura::client::GetScreenPositionClient(windows_.window2->GetRootWindow())->
       ConvertPointFromScreen(windows_.window2->parent(), &location_in_parent);
   std::vector<aura::Window*> windows;
   windows.push_back(windows_.window2);
+  DCHECK(windows_.other_windows.empty());
   FindWindowsTouching(windows_.window2, windows_.direction,
                       &windows_.other_windows);
   for (size_t i = 0; i < windows_.other_windows.size(); ++i) {
     windows_.other_windows[i]->AddObserver(this);
     windows.push_back(windows_.other_windows[i]);
   }
   int component = windows_.direction == LEFT_RIGHT ? HTRIGHT : HTBOTTOM;
   window_resizer_.reset(WorkspaceWindowResizer::Create(
       windows_.window1, location_in_parent, component, windows));
 }
@@ skipping 14 matching lines @@
     bounds.set_x(show_bounds_in_screen_.x());
   resize_widget_->SetBounds(bounds);
 }
 
 void MultiWindowResizeController::CompleteResize(int event_flags) {
   window_resizer_->CompleteDrag(event_flags);
   window_resizer_.reset();
 
   // Mouse may still be over resizer, if not hide.
   gfx::Point screen_loc = gfx::Screen::GetCursorScreenPoint();
-  if (!resize_widget_->GetWindowBoundsInScreen().Contains(screen_loc))
+  if (!resize_widget_->GetWindowBoundsInScreen().Contains(screen_loc)) {
     Hide();
+  } else {
+    // If the mouse is over the resizer we need to remove observers on any of
+    // the |other_windows|. If we start another resize we'll recalculate the
+    // |other_windows| and invoke AddObserver() as necessary.
+    for (size_t i = 0; i < windows_.other_windows.size(); ++i)
+      windows_.other_windows[i]->RemoveObserver(this);
+    windows_.other_windows.clear();
+  }
 }
 
 void MultiWindowResizeController::CancelResize() {
   if (!window_resizer_.get())
     return;  // Happens if window was destroyed and we nuked the WindowResizer.
   window_resizer_->RevertDrag();
   window_resizer_.reset();
   Hide();
 }
 
@@ skipping 49 matching lines @@
 
   gfx::Point window_loc(location_in_screen);
   aura::Window::ConvertPointToWindow(
       window->GetRootWindow(), window, &window_loc);
   return window->HitTest(window_loc) &&
       window->delegate()->GetNonClientComponent(window_loc) == component;
 }
 
 }  // namespace internal
 }  // namespace ash