Fully support the autohide shelf option for touch UI on Windows.

ash/shelf/shelf_layout_manager.cc

Index: ash/shelf/shelf_layout_manager.cc
diff --git a/ash/shelf/shelf_layout_manager.cc b/ash/shelf/shelf_layout_manager.cc
index 3b257b07ca6924122135a75492d13ac5b8cfca8c..db23f594d37c0c1f72a94633d41474186745cedf 100644
--- a/ash/shelf/shelf_layout_manager.cc
+++ b/ash/shelf/shelf_layout_manager.cc
@@ -389,7 +389,35 @@ void ShelfLayoutManager::RemoveObserver(ShelfLayoutManagerObserver* observer) {
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-// ShelfLayoutManager, Gesture dragging:
+// ShelfLayoutManager, Gesture functions:
+
+#if defined(OS_WIN)
+void ShelfLayoutManager::OnGestureEdgeSwipe(const ui::GestureEvent& gesture) {
+  // Edge swipe should exit fullscreen, show the tray, and disable auto-hide.
+
+  if (workspace_controller_->GetWindowState() ==
+      WORKSPACE_WINDOW_STATE_FULL_SCREEN) {
+    const std::vector<aura::Window*> windows =
+        ash::MruWindowTracker::BuildWindowList(false);
+
+    for (size_t i = 0; i < windows.size(); ++i) {
+      if (windows[i] && windows[i]->IsVisible() &&
+          root_window_ == windows[i]->GetRootWindow()) {
+        wm::WindowState* window_state = wm::GetWindowState(windows[i]);
+        if (window_state->IsFullscreen())
+          window_state->ToggleFullscreen();
+      }
+    }
+  }
+
+  ShelfVisibilityState visibility = CalculateShelfVisibility();
+  if (visibility == SHELF_AUTO_HIDE &&
+      CalculateAutoHideState(visibility) == SHELF_AUTO_HIDE_HIDDEN) {
+    SetState(SHELF_VISIBLE);
+    SetAutoHideBehavior(SHELF_AUTO_HIDE_BEHAVIOR_NEVER);
+  }
+}
+#endif
 
 void ShelfLayoutManager::StartGestureDrag(const ui::GestureEvent& gesture) {
   gesture_drag_status_ = GESTURE_DRAG_IN_PROGRESS;