Attempt 3: Makes managed mode constrain the height of windows so they don't

ash/wm/workspace/workspace_event_filter.cc

Index: ash/wm/workspace/workspace_event_filter.cc
diff --git a/ash/wm/workspace/workspace_event_filter.cc b/ash/wm/workspace/workspace_event_filter.cc
index e64bc901bf94e5f0f84b089379761ea2a5b1654d..0fe8bb2b9ebee1c15813e4d0e13a4f6a10978c68 100644
--- a/ash/wm/workspace/workspace_event_filter.cc
+++ b/ash/wm/workspace/workspace_event_filter.cc
@@ -7,6 +7,7 @@
 #include "ash/wm/window_frame.h"
 #include "ash/wm/window_util.h"
 #include "ash/wm/workspace/workspace_layout_manager.h"
+#include "ash/wm/workspace/workspace_window_resizer.h"
 #include "ui/aura/event.h"
 #include "ui/aura/window.h"
 #include "ui/base/hit_test.h"
@@ -31,8 +32,6 @@ namespace internal {
 
 WorkspaceEventFilter::WorkspaceEventFilter(aura::Window* owner)
     : ToplevelWindowEventFilter(owner),
-      owner_(owner),
-      drag_state_(DRAG_NONE),
       hovered_window_(NULL) {
 }
 
@@ -43,57 +42,18 @@ WorkspaceEventFilter::~WorkspaceEventFilter() {
 
 bool WorkspaceEventFilter::PreHandleMouseEvent(aura::Window* target,
                                                aura::MouseEvent* event) {
-  WorkspaceLayoutManager* layout_manager =
-      static_cast<WorkspaceLayoutManager*>(owner_->layout_manager());
-  DCHECK(layout_manager);
-
-  // TODO(oshima|derat): Incorporate the logic below and introduce DragObserver
-  // (or something similar) to decouple DCLM.
-
-  // Notify layout manager that drag event may move/resize the target wnidow.
-  if (event->type() == ui::ET_MOUSE_DRAGGED && drag_state_ == DRAG_NONE)
-    layout_manager->PrepareForMoveOrResize(target, event);
-
-  bool handled = ToplevelWindowEventFilter::PreHandleMouseEvent(target, event);
-
   switch (event->type()) {
-    case ui::ET_MOUSE_DRAGGED:
-      // Cancel move/resize if the event wasn't handled, or
-      // drag_state_ didn't move to MOVE or RESIZE.
-      if (handled) {
-        switch (drag_state_) {
-          case DRAG_NONE:
-            if (!UpdateDragState())
-              layout_manager->CancelMoveOrResize(target, event);
-            break;
-          case DRAG_MOVE:
-            layout_manager->ProcessMove(target, event);
-            break;
-          case DRAG_RESIZE:
-            break;
-        }
-      } else {
-        layout_manager->CancelMoveOrResize(target, event);
-      }
-      break;
     case ui::ET_MOUSE_ENTERED:
       UpdateHoveredWindow(GetActivatableWindow(target));
       break;
+    case ui::ET_MOUSE_CAPTURE_CHANGED:
     case ui::ET_MOUSE_EXITED:
       UpdateHoveredWindow(NULL);
       break;
-    case ui::ET_MOUSE_RELEASED:
-      if (drag_state_ == DRAG_MOVE)
-        layout_manager->EndMove(target, event);
-      else if (drag_state_ == DRAG_RESIZE)
-        layout_manager->EndResize(target, event);
-
-      drag_state_ = DRAG_NONE;
-      break;
     default:
       break;
   }
-  return handled;
+  return ToplevelWindowEventFilter::PreHandleMouseEvent(target, event);
 }
 
 void WorkspaceEventFilter::OnWindowDestroyed(aura::Window* window) {
@@ -102,9 +62,12 @@ void WorkspaceEventFilter::OnWindowDestroyed(aura::Window* window) {
   hovered_window_ = NULL;
 }
 
-bool WorkspaceEventFilter::UpdateDragState() {
-  // TODO(sky): nuke this method.
-  return false;
+WindowResizer* WorkspaceEventFilter::CreateWindowResizer(
+    aura::Window* window,
+    const gfx::Point& point,
+    int window_component) {
+  return
+      new WorkspaceWindowResizer(window, point, window_component, grid_size());
 }
 
 void WorkspaceEventFilter::UpdateHoveredWindow(