Attempt 2: Allows tab dragging when maximized on aura. To fix it I made it so

ash/wm/workspace/workspace_window_resizer.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/workspace_window_resizer.h"
 
+#include "ash/wm/window_util.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_delegate.h"
 #include "ui/aura/window_property.h"
 #include "ui/base/hit_test.h"
 #include "ui/gfx/compositor/scoped_layer_animation_settings.h"
 #include "ui/gfx/compositor/layer.h"
 #include "ui/gfx/screen.h"
 #include "ui/gfx/transform.h"
 
 DECLARE_WINDOW_PROPERTY_TYPE(int)
 
 namespace ash {
 namespace internal {
 
 namespace {
 
 const aura::WindowProperty<int> kHeightBeforeObscuredProp = {0};
 const aura::WindowProperty<int>* const kHeightBeforeObscuredKey =
     &kHeightBeforeObscuredProp;
 
 }  // namespace
 
 WorkspaceWindowResizer::WorkspaceWindowResizer(aura::Window* window,
                                                const gfx::Point& location,
                                                int window_component,
                                                int grid_size)
-    : WindowResizer(window, location, window_component, grid_size) {
+    : WindowResizer(window, location, window_component, grid_size),
+      constrain_size_(wm::IsWindowNormal(window)) {
   if (is_resizable() && GetHeightBeforeObscured(window) &&
+      constrain_size_ &&
       (!WindowTouchesBottomOfScreen() ||
        bounds_change() != kBoundsChange_Repositions)) {
     ClearHeightBeforeObscured(window);
   }
 }
 
 WorkspaceWindowResizer::~WorkspaceWindowResizer() {
 }
 
 gfx::Rect WorkspaceWindowResizer::GetBoundsForDrag(const gfx::Point& location) {
@@ skipping 32 matching lines @@
 void WorkspaceWindowResizer::ClearHeightBeforeObscured(aura::Window* window) {
   window->SetProperty(kHeightBeforeObscuredKey, 0);
 }
 
 // static
 int WorkspaceWindowResizer::GetHeightBeforeObscured(aura::Window* window) {
   return window->GetProperty(kHeightBeforeObscuredKey);
 }
 
 void WorkspaceWindowResizer::AdjustBounds(gfx::Rect* bounds) const {
+  if (!constrain_size_)
+    return;
+
   gfx::Rect work_area(gfx::Screen::GetMonitorWorkAreaNearestWindow(window()));
   if (bounds->bottom() < work_area.bottom()) {
     int height = GetHeightBeforeObscured(window());
     if (!height)
       return;
     height = std::max(bounds->height(), height);
     bounds->set_height(std::min(work_area.bottom() - bounds->y(), height));
     return;
   }
 
@@ skipping 11 matching lines @@
   }
 }
 
 bool WorkspaceWindowResizer::WindowTouchesBottomOfScreen() const {
   gfx::Rect work_area(gfx::Screen::GetMonitorWorkAreaNearestWindow(window()));
   return window()->bounds().bottom() == work_area.bottom();
 }
 
 }  // namespace internal
 }  // namespace ash