Remove GridLayout::SetInsets in favor of an empty border on the host.

ui/views/layout/grid_layout.h

Index: ui/views/layout/grid_layout.h
diff --git a/ui/views/layout/grid_layout.h b/ui/views/layout/grid_layout.h
index 197d101705caa195f5fd7c98fc20ab973187dc93..e5e3412d89904d3552d65dcead79a4b81c245ced 100644
--- a/ui/views/layout/grid_layout.h
+++ b/ui/views/layout/grid_layout.h
@@ -104,13 +104,10 @@ class VIEWS_EXPORT GridLayout : public LayoutManager {
   explicit GridLayout(View* host);
   ~GridLayout() override;
 
-  // Creates a GridLayout with kPanel*Margin insets.
+  // Creates a GridLayout, assigns it as the LayoutManager of |host|, and gives
+  // it a INSETS_PANEL-sized padding border.
   static GridLayout* CreatePanel(View* host);
 
-  // Sets the insets. All views are placed relative to these offsets.
-  void SetInsets(int top, int left, int bottom, int right);
-  void SetInsets(const gfx::Insets& insets);
-
   // Creates a new column set with the specified id and returns it.
   // The id is later used when starting a new row.
   // GridLayout takes ownership of the ColumnSet and will delete it when
@@ -239,9 +236,6 @@ class VIEWS_EXPORT GridLayout : public LayoutManager {
   // Column set for the current row. This is null for padding rows.
   ColumnSet* current_row_col_set_;
 
-  // Insets.
-  gfx::Insets insets_;
-
   // Set to true when adding a View.
   bool adding_view_;