Fix app list drag view being hidden on reparent when synchronous drag is setting up.

ui/app_list/views/apps_grid_view.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 "ui/app_list/views/apps_grid_view.h"
 
 #include <algorithm>
 #include <set>
 #include <string>
 
@@ skipping 199 matching lines @@
         drag_view_offset_(drag_view_offset),
         has_shortcut_path_(false),
         running_(false),
         canceled_(false) {}
 
   void set_shortcut_path(const base::FilePath& shortcut_path) {
     has_shortcut_path_ = true;
     shortcut_path_ = shortcut_path;
   }
 
+  bool running() { return running_; }
+
   bool CanRun() {
     return has_shortcut_path_ && !running_;
   }
 
   void Run() {
     DCHECK(CanRun());
 
     // Prevent the synchronous dragger being destroyed while the drag is
     // running.
     scoped_refptr<SynchronousDrag> this_ref = this;
@@ skipping 254 matching lines @@
     return;
   delegate_->GetShortcutPathForApp(
       drag_view_->item()->id(),
       base::Bind(&AppsGridView::OnDelayShortcutPath, base::Unretained(this)));
   synchronous_drag_ = new SynchronousDrag(this, drag_view_, drag_view_offset_);
 #endif
 }
 
 bool AppsGridView::RunSynchronousDrag() {
 #if defined(OS_WIN)
-  if (synchronous_drag_ && synchronous_drag_->CanRun()) {
+  if (!synchronous_drag_)
+    return false;
+
+  if (synchronous_drag_->CanRun()) {
+    if (IsDraggingForReparentInHiddenGridView())
+      folder_delegate_->SetRootLevelDragViewVisible(false);
     synchronous_drag_->Run();
     synchronous_drag_ = NULL;
     return true;
+  } else if (!synchronous_drag_->running()) {

[tapted, 2014/05/02 01:52:47]

nit: I think the condition is redundant (i.e. can just be else {)

That is, because the Run() above would immediately run it, there's never a state
where running is true and CanRun is false.

(running && !CanRun)
  ==> (running && !(has_shortcut_path_ && !running_)
  ==> (running && (!has_shortcut_path  || running)
  ==> (running && !has_shortcut_path)
  ==> (has_shortcut_path && !has_shortcut_path)

(because running ==> CanRun was true at least once, requiring has_shortcut_path
to be true)

So paradox means !canrun ==> !running so this `if` is always true.

But my brain hurts now

[calamity, 2014/05/02 04:28:38]

Ah, true.

+    // The OS drag is not ready yet. If the root grid has a drag view because
+    // a reparent has started, ensure it is visible.
+    if (IsDraggingForReparentInHiddenGridView())
+      folder_delegate_->SetRootLevelDragViewVisible(true);
   }
 #endif
   return false;
 }
 
 void AppsGridView::CleanUpSynchronousDrag() {
 #if defined(OS_WIN)
   if (synchronous_drag_)
     synchronous_drag_->EndDragExternally();
 
@@ skipping 251 matching lines @@
   drop_target_ = Index();
   if (!cancel_reparent && drag_view_)
     drag_view_->OnDragEnded();
   drag_view_ = NULL;
   drag_start_grid_view_ = gfx::Point();
   drag_start_page_ = -1;
   drag_view_offset_ = gfx::Point();
   dragging_for_reparent_item_ = false;
 }
 
+void AppsGridView::SetDragViewVisible(bool visible) {
+  DCHECK(drag_view_);
+  SetViewHidden(drag_view_, !visible, true);
+}
+
 void AppsGridView::SetDragAndDropHostOfCurrentAppList(
     ApplicationDragAndDropHost* drag_and_drop_host) {
   drag_and_drop_host_ = drag_and_drop_host;
 }
 
 void AppsGridView::Prerender(int page_index) {
   Layout();
   int start = std::max(0, (page_index - kPrerenderPages) * tiles_per_page());
   int end = std::min(view_model_.view_size(),
                      (page_index + 1 + kPrerenderPages) * tiles_per_page());
@@ skipping 1299 matching lines @@
 void AppsGridView::SetAsFolderDroppingTarget(const Index& target_index,
                                              bool is_target_folder) {
   AppListItemView* target_view =
       static_cast<AppListItemView*>(
           GetViewAtSlotOnCurrentPage(target_index.slot));
   if (target_view)
     target_view->SetAsAttemptedFolderTarget(is_target_folder);
 }
 
 }  // namespace app_list