Use a weak pointer to determine if resizer was destroyed by nested Drag calls.

BUG=None
TEST=*ResizerTest.*

Review URL: https://chromiumcodereview.appspot.com/23645008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@221790 0039d316-1c4b-4281-b951-d872f2087c98

ash/wm/dock/docked_window_resizer.cc

@@ -20,6 +20,7 @@
 #include "ash/wm/workspace/phantom_window_controller.h"
 #include "ash/wm/workspace/workspace_window_resizer.h"
 #include "base/command_line.h"
+#include "base/memory/weak_ptr.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/env.h"
 #include "ui/aura/root_window.h"
@@ -47,8 +48,6 @@ DockedWindowLayoutManager* GetDockedLayoutManagerAtPoint(
 }  // namespace
 
 DockedWindowResizer::~DockedWindowResizer() {
-  if (destroyed_)
-    *destroyed_ = true;
 }
 
 // static
@@ -66,7 +65,6 @@ DockedWindowResizer::Create(WindowResizer* next_window_resizer,
 void DockedWindowResizer::Drag(const gfx::Point& location, int event_flags) {
   last_location_ = location;
   wm::ConvertPointToScreen(GetTarget()->parent(), &last_location_);
-  bool destroyed = false;
   if (!did_move_or_resize_) {
     did_move_or_resize_ = true;
     StartedDragging();
@@ -83,15 +81,12 @@ void DockedWindowResizer::Drag(const gfx::Point& location, int event_flags) {
     SetTrackedByWorkspace(GetTarget(), false);
   gfx::Point modified_location(location.x() + offset.x(),
                                location.y() + offset.y());
-  destroyed_ = &destroyed;
-  next_window_resizer_->Drag(modified_location, event_flags);
 
-  // TODO(varkha): Refactor the way WindowResizer calls into other window
-  // resizers to avoid the awkward pattern here for checking if
-  // next_window_resizer_ destroys the resizer object.
-  if (destroyed)
+  base::WeakPtr<DockedWindowResizer> resizer(weak_ptr_factory_.GetWeakPtr());
+  next_window_resizer_->Drag(modified_location, event_flags);
+  if (!resizer)
     return;
-  destroyed_ = NULL;
+
   if (set_tracked_by_workspace)
     SetTrackedByWorkspace(GetTarget(), tracked_by_workspace);
 
@@ -185,7 +180,7 @@ DockedWindowResizer::DockedWindowResizer(WindowResizer* next_window_resizer,
       did_move_or_resize_(false),
       was_docked_(false),
       is_docked_(false),
-      destroyed_(NULL) {
+      weak_ptr_factory_(this) {
   DCHECK(details_.is_resizable);
   aura::Window* dock_container = Shell::GetContainer(
       details.window->GetRootWindow(),

ash/wm/dock/docked_window_resizer.h

@@ -9,6 +9,7 @@
 #include "ash/wm/window_resizer.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
 
 namespace gfx {
 class Point;
@@ -98,9 +99,7 @@ class ASH_EXPORT DockedWindowResizer : public WindowResizer {
   // True if the dragged window is docked during the drag.
   bool is_docked_;
 
-  // If non-NULL the destructor sets this to true. Used to determine if this has
-  // been deleted.
-  bool* destroyed_;
+  base::WeakPtrFactory<DockedWindowResizer> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DockedWindowResizer);
 };

ash/wm/drag_window_resizer.cc

@@ -10,6 +10,7 @@
 #include "ash/wm/coordinate_conversion.h"
 #include "ash/wm/drag_window_controller.h"
 #include "ash/wm/property_util.h"
+#include "base/memory/weak_ptr.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/env.h"
 #include "ui/aura/root_window.h"
@@ -56,9 +57,6 @@ DragWindowResizer::~DragWindowResizer() {
   shell->mouse_cursor_filter()->HideSharedEdgeIndicator();
   if (instance_ == this)
     instance_ = NULL;
-
-  if (destroyed_)
-    *destroyed_ = true;
 }
 
 // static
@@ -74,18 +72,12 @@ DragWindowResizer* DragWindowResizer::Create(
 }
 
 void DragWindowResizer::Drag(const gfx::Point& location, int event_flags) {
-  bool destroyed = false;
-  destroyed_ = &destroyed;
+  base::WeakPtr<DragWindowResizer> resizer(weak_ptr_factory_.GetWeakPtr());
   next_window_resizer_->Drag(location, event_flags);
-
-  // TODO(flackr): Refactor the way WindowResizer calls into other window
-  // resizers to avoid the awkward pattern here for checking if
-  // next_window_resizer_ destroys the resizer object.
-  if (destroyed)
+  if (!resizer)
     return;
-  destroyed_ = NULL;
-  last_mouse_location_ = location;
 
+  last_mouse_location_ = location;
   // Show a phantom window for dragging in another root window.
   if (HasSecondaryRootWindow()) {
     gfx::Point location_in_screen = location;
@@ -140,7 +132,7 @@ DragWindowResizer::DragWindowResizer(WindowResizer* next_window_resizer,
                                      const Details& details)
     : next_window_resizer_(next_window_resizer),
       details_(details),
-      destroyed_(NULL) {
+      weak_ptr_factory_(this) {
   // The pointer should be confined in one display during resizing a window
   // because the window cannot span two displays at the same time anyway. The
   // exception is window/tab dragging operation. During that operation,

ash/wm/drag_window_resizer.h

@@ -8,6 +8,7 @@
 #include "ash/wm/window_resizer.h"
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
+#include "base/memory/weak_ptr.h"
 #include "ui/gfx/point.h"
 
 namespace ash {
@@ -62,13 +63,11 @@ class ASH_EXPORT DragWindowResizer : public WindowResizer {
 
   gfx::Point last_mouse_location_;
 
-  // If non-NULL the destructor sets this to true. Used to determine if this has
-  // been deleted.
-  bool* destroyed_;
-
   // Current instance for use by the DragWindowResizerTest.
   static DragWindowResizer* instance_;
 
+  base::WeakPtrFactory<DragWindowResizer> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(DragWindowResizer);
 };
 

ash/wm/panels/panel_window_resizer.cc

@@ -15,6 +15,7 @@
 #include "ash/wm/panels/panel_layout_manager.h"
 #include "ash/wm/property_util.h"
 #include "ash/wm/window_properties.h"
+#include "base/memory/weak_ptr.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/env.h"
 #include "ui/aura/root_window.h"
@@ -40,8 +41,6 @@ internal::PanelLayoutManager* GetPanelLayoutManager(
 }  // namespace
 
 PanelWindowResizer::~PanelWindowResizer() {
-  if (destroyed_)
-    *destroyed_ = true;
 }
 
 // static
@@ -59,7 +58,6 @@ PanelWindowResizer::Create(WindowResizer* next_window_resizer,
 void PanelWindowResizer::Drag(const gfx::Point& location, int event_flags) {
   last_location_ = location;
   wm::ConvertPointToScreen(GetTarget()->parent(), &last_location_);
-  bool destroyed = false;
   if (!did_move_or_resize_) {
     did_move_or_resize_ = true;
     StartedDragging();
@@ -93,15 +91,12 @@ void PanelWindowResizer::Drag(const gfx::Point& location, int event_flags) {
   should_attach_ = AttachToLauncher(bounds, &offset);
   gfx::Point modified_location(location.x() + offset.x(),
                                location.y() + offset.y());
-  destroyed_ = &destroyed;
-  next_window_resizer_->Drag(modified_location, event_flags);
 
-  // TODO(flackr): Refactor the way WindowResizer calls into other window
-  // resizers to avoid the awkward pattern here for checking if
-  // next_window_resizer_ destroys the resizer object.
-  if (destroyed)
+  base::WeakPtr<PanelWindowResizer> resizer(weak_ptr_factory_.GetWeakPtr());
+  next_window_resizer_->Drag(modified_location, event_flags);
+  if (!resizer)
     return;
-  destroyed_ = NULL;
+
   if (should_attach_ &&
       !(details_.bounds_change & WindowResizer::kBoundsChange_Resizes)) {
     UpdateLauncherPosition();
@@ -137,7 +132,7 @@ PanelWindowResizer::PanelWindowResizer(WindowResizer* next_window_resizer,
       did_move_or_resize_(false),
       was_attached_(GetTarget()->GetProperty(internal::kPanelAttachedKey)),
       should_attach_(was_attached_),
-      destroyed_(NULL) {
+      weak_ptr_factory_(this) {
   DCHECK(details_.is_resizable);
   panel_container_ = Shell::GetContainer(
       details.window->GetRootWindow(),

ash/wm/panels/panel_window_resizer.h

@@ -7,6 +7,7 @@
 
 #include "ash/wm/window_resizer.h"
 #include "base/compiler_specific.h"
+#include "base/memory/weak_ptr.h"
 
 namespace gfx {
 class Rect;
@@ -83,9 +84,7 @@ class ASH_EXPORT PanelWindowResizer : public WindowResizer {
   // True if the window should attach to the launcher after releasing.
   bool should_attach_;
 
-  // If non-NULL the destructor sets this to true. Used to determine if this has
-  // been deleted.
-  bool* destroyed_;
+  base::WeakPtrFactory<PanelWindowResizer> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PanelWindowResizer);
 };