Refactor app list so AppsGridView owns the PaginationModel.

ui/app_list/views/app_list_main_view.cc

Index: ui/app_list/views/app_list_main_view.cc
diff --git a/ui/app_list/views/app_list_main_view.cc b/ui/app_list/views/app_list_main_view.cc
index dcb57803c4acf6d55539b8c7838c12b0baa27f7b..f8a9c3b333d311ed0ecdcd1d65169779ef128a96 100644
--- a/ui/app_list/views/app_list_main_view.cc
+++ b/ui/app_list/views/app_list_main_view.cc
@@ -21,6 +21,7 @@
 #include "ui/app_list/search_box_model.h"
 #include "ui/app_list/views/app_list_item_view.h"
 #include "ui/app_list/views/apps_container_view.h"
+#include "ui/app_list/views/apps_grid_view.h"
 #include "ui/app_list/views/contents_switcher_view.h"
 #include "ui/app_list/views/contents_view.h"
 #include "ui/app_list/views/search_box_view.h"
@@ -83,17 +84,13 @@ class AppListMainView::IconLoader : public AppListItemObserver {
 // AppListMainView:
 
 AppListMainView::AppListMainView(AppListViewDelegate* delegate,
-                                 PaginationModel* pagination_model,
                                  gfx::NativeView parent)
     : delegate_(delegate),
-      pagination_model_(pagination_model),
+      pagination_model_(NULL),
       model_(delegate->GetModel()),
       search_box_view_(NULL),
       contents_view_(NULL),
       weak_ptr_factory_(this) {
-  // Starts icon loading early.
-  PreloadIcons(parent);
-
   SetLayoutManager(new views::BoxLayout(views::BoxLayout::kVertical,
                                         kInnerPadding,
                                         kInnerPadding,
@@ -104,15 +101,24 @@ AppListMainView::AppListMainView(AppListViewDelegate* delegate,
   AddContentsView();
   if (app_list::switches::IsExperimentalAppListEnabled())
     AddChildView(new ContentsSwitcherView(contents_view_));
+  pagination_model_ = contents_view_->apps_container_view()
+                          ->apps_grid_view()
+                          ->GetPaginationModel();

[xiyuan, 2014/05/30 15:47:47]

Can we get rid of |pagination_model_| as a member and replace it with an
accessor?

[tapted, 2014/06/02 04:02:21]

hehe - that was going to be first comment too :). I tend to prefer accessors
into children rather than weak pointers to their members.  (wow that sentence
sounds so wrong).  It, uh, makes the ownership very clear rather than having to
rely on comments.

[Matt Giuca, 2014/06/02 07:11:23]

Done.

+
+  // Starts icon loading early.
+  PreloadIcons(parent);
 }
 
 void AppListMainView::AddContentsView() {
-  contents_view_ = new ContentsView(
-      this, pagination_model_, model_, delegate_);
+  contents_view_ = new ContentsView(this, model_, delegate_);
   AddChildViewAt(contents_view_, kContentsViewIndex);
 
   search_box_view_->set_contents_view(contents_view_);
 
+  pagination_model_ = contents_view_->apps_container_view()
+                          ->apps_grid_view()
+                          ->GetPaginationModel();
+
 #if defined(USE_AURA)
   contents_view_->SetPaintToLayer(true);
   contents_view_->SetFillsBoundsOpaquely(false);
@@ -160,9 +166,10 @@ void AppListMainView::ModelChanged() {
   pending_icon_loaders_.clear();
   model_ = delegate_->GetModel();
   search_box_view_->ModelChanged();
+  pagination_model_->SelectPage(0, false /* animate */);

[tapted, 2014/06/02 04:02:21]

this is perhaps not needed any more? Or, it needs a comment like ~"communicate
to observers to reset back to foo", since the model will get deleted on the next
line, so it feels weird that you need to set some state on it first.

Also (depending on the reasons), it might be better to do this in
~AppsGridView() or similar anyway

[Matt Giuca, 2014/06/02 07:11:23]

Ah I see. The reason this was there before was because switching profiles would
otherwise take you to the app list page for the previous profile (because the
PaginationModel was global).

I'm actually fixing this hack because now a fresh PaginationModel is created for
the new profile -- as it should be!

   delete contents_view_;
   contents_view_ = NULL;
-  pagination_model_->SelectPage(0, false /* animate */);
+  pagination_model_ = NULL;
   AddContentsView();
   Layout();
 }