Store AppItems as pages in AppListModel.

ui/app_list/cocoa/apps_grid_controller.mm

Index: ui/app_list/cocoa/apps_grid_controller.mm
diff --git a/ui/app_list/cocoa/apps_grid_controller.mm b/ui/app_list/cocoa/apps_grid_controller.mm
index 5fad26fe8d5c058bab659fd6983c0e3d52376a9f..48f16f80403348c9a3e55723c8d637cea8df0be9 100644
--- a/ui/app_list/cocoa/apps_grid_controller.mm
+++ b/ui/app_list/cocoa/apps_grid_controller.mm
@@ -93,26 +93,30 @@ NSTimeInterval g_scroll_duration = 0.18;
 
 namespace app_list {
 
-class AppsGridDelegateBridge : public ui::ListModelObserver {
+class AppsGridDelegateBridge : public AppListModelObserver {
  public:
   AppsGridDelegateBridge(AppsGridController* parent) : parent_(parent) {}
 
  private:
   // Overridden from ui::ListModelObserver:
-  virtual void ListItemsAdded(size_t start, size_t count) OVERRIDE {
-    [parent_ listItemsAdded:start
+  virtual void OnListItemsAdded(size_t page_index,
+                                size_t start, size_t count) OVERRIDE {
+    size_t start_index = page_index * kItemsPerPage + start;
+    [parent_ listItemsAdded:start_index
                       count:count];
   }
-  virtual void ListItemsRemoved(size_t start, size_t count) OVERRIDE {
-    [parent_ listItemsRemoved:start
+  virtual void OnListItemsRemoved(size_t page_index,
+                                  size_t start, size_t count) OVERRIDE {
+    size_t start_index = page_index * kItemsPerPage + start;
+    [parent_ listItemsRemoved:start_index
                         count:count];
   }
-  virtual void ListItemMoved(size_t index, size_t target_index) OVERRIDE {
-    [parent_ listItemMovedFromIndex:index
-                       toModelIndex:target_index];
-  }
-  virtual void ListItemsChanged(size_t start, size_t count) OVERRIDE {
-    NOTREACHED();
+  virtual void OnListItemMoved(size_t page_index,
+                               size_t index, size_t target_index) OVERRIDE {
+    size_t from_index = page_index * kItemsPerPage + index;
+    size_t to_index = page_index * kItemsPerPage + target_index;
+    [parent_ listItemMovedFromIndex:from_index
+                       toModelIndex:to_index];
   }
 
   AppsGridController* parent_;  // Weak, owns us.
@@ -188,7 +192,7 @@ class AppsGridDelegateBridge : public ui::ListModelObserver {
 
 - (void)setModel:(scoped_ptr<app_list::AppListModel>)newModel {
   if (model_) {
-    model_->apps()->RemoveObserver(bridge_.get());
+    model_->RemoveObserver(bridge_.get());
 
     // Since the model is about to be deleted, and the AppKit objects might be
     // sitting in an NSAutoreleasePool, ensure there are no references to the
@@ -205,9 +209,12 @@ class AppsGridDelegateBridge : public ui::ListModelObserver {
   if (!model_)
     return;
 
-  model_->apps()->AddObserver(bridge_.get());
-  [self listItemsAdded:0
-                 count:model_->apps()->item_count()];
+  model_->AddObserver(bridge_.get());
+  for (size_t p = 0; p < model_->GetNumAppPages(); ++p) {
+    size_t start_index = p * kItemsPerPage;
+    [self listItemsAdded:start_index
+                   count:model_->GetAppItemsForPage(p).item_count()];
+  }
 }
 
 - (void)setDelegate:(app_list::AppListViewDelegate*)newDelegate {
@@ -522,9 +529,13 @@ class AppsGridDelegateBridge : public ui::ListModelObserver {
   if (itemIndex == modelIndex)
     return;
 
-  model_->apps()->RemoveObserver(bridge_.get());
-  model_->apps()->Move(itemIndex, modelIndex);
-  model_->apps()->AddObserver(bridge_.get());
+  size_t itemPageIndex = itemIndex / kItemsPerPage;
+  itemIndex -= itemPageIndex * kItemsPerPage;
+  size_t modelPageIndex = modelIndex / kItemsPerPage;
+  modelIndex -= modelPageIndex * kItemsPerPage;
+  model_->RemoveObserver(bridge_.get());
+  model_->MoveItem(itemPageIndex, itemIndex, modelPageIndex, modelIndex);
+  model_->AddObserver(bridge_.get());
 }
 
 - (AppsCollectionViewDragManager*)dragManager {
@@ -541,7 +552,9 @@ class AppsGridDelegateBridge : public ui::ListModelObserver {
   [dragManager_ cancelDrag];
 
   for (size_t i = start; i < start + count; ++i) {
-    app_list::AppListItemModel* itemModel = model_->apps()->GetItemAt(i);
+    size_t page = i / kItemsPerPage;
+    size_t index = i - page * kItemsPerPage;
+    app_list::AppListItemModel* itemModel = model_->GetItemAt(page, index);
     [items_ insertObject:[NSValue valueWithPointer:itemModel]
                  atIndex:i];
   }