Add pretargethandler to exit overview mode on touch/click.

Touching or clicking on the background page while in overview mode will now
dismiss it.

BUG=364507

TEST=TBA

Review URL: https://codereview.chromium.org/435023003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@287601 0039d316-1c4b-4281-b951-d872f2087c98

ash/desktop_background/desktop_background_view.cc

@@ -15,6 +15,7 @@
 #include "ash/session/session_state_delegate.h"
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
+#include "ash/wm/overview/window_selector_controller.h"
 #include "ash/wm/window_animations.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/utf_string_conversions.h"
@@ -72,14 +73,51 @@ class LayerControlView : public views::View {
 
 }  // namespace
 
+// This event handler receives events in the pre-target phase and takes care of
+// the following:
+//   - Disabling overview mode on touch release.
+//   - Disabling overview mode on mouse release.
+class PreEventDispatchHandler : public ui::EventHandler {
+ public:
+  PreEventDispatchHandler() {}
+  virtual ~PreEventDispatchHandler() {}
+
+ private:
+  // ui::EventHandler:
+  virtual void OnMouseEvent(ui::MouseEvent* event) OVERRIDE {
+    CHECK_EQ(ui::EP_PRETARGET, event->phase());
+    WindowSelectorController* controller =
+        Shell::GetInstance()->window_selector_controller();
+    if (event->type() == ui::ET_MOUSE_RELEASED && controller->IsSelecting()) {
+      controller->ToggleOverview();
+      event->StopPropagation();
+    }
+  }
+
+  virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE {
+    CHECK_EQ(ui::EP_PRETARGET, event->phase());
+    WindowSelectorController* controller =
+        Shell::GetInstance()->window_selector_controller();
+    if (event->type() == ui::ET_GESTURE_TAP && controller->IsSelecting()) {
+      controller->ToggleOverview();
+      event->StopPropagation();
+    }
+  }
+
+  DISALLOW_COPY_AND_ASSIGN(PreEventDispatchHandler);
+};
+
 ////////////////////////////////////////////////////////////////////////////////
 // DesktopBackgroundView, public:
 
-DesktopBackgroundView::DesktopBackgroundView() {
+DesktopBackgroundView::DesktopBackgroundView()
+    : pre_dispatch_handler_(new PreEventDispatchHandler()) {
   set_context_menu_controller(this);
+  AddPreTargetHandler(pre_dispatch_handler_.get());
 }
 
 DesktopBackgroundView::~DesktopBackgroundView() {
+  RemovePreTargetHandler(pre_dispatch_handler_.get());
 }
 
 ////////////////////////////////////////////////////////////////////////////////

ash/desktop_background/desktop_background_view.h

@@ -5,12 +5,15 @@
 #ifndef ASH_DESKTOP_BACKGROUND_DESKTOP_BACKGROUND_VIEW_H_
 #define ASH_DESKTOP_BACKGROUND_DESKTOP_BACKGROUND_VIEW_H_
 
+#include "ui/events/event.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/views/context_menu_controller.h"
 #include "ui/views/view.h"
 
 namespace ash {
 
+class PreEventDispatchHandler;
+
 class DesktopBackgroundView : public views::View,
                               public views::ContextMenuController {
  public:
@@ -26,6 +29,7 @@ class DesktopBackgroundView : public views::View,
   virtual void ShowContextMenuForView(views::View* source,
                                       const gfx::Point& point,
                                       ui::MenuSourceType source_type) OVERRIDE;
+  scoped_ptr<PreEventDispatchHandler> pre_dispatch_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(DesktopBackgroundView);
 };