[gnome-usage] Graph-Stack-Switcher: Set correct button active on scroll

[Petr Štětka <pstetka src gnome org>]

commit a946602121d83264fb54af483da16598584da1bd
Author: Yash Yadav <yashdimpu gmail com>
Date:   Mon Mar 18 19:37:12 2019 +0530

    Graph-Stack-Switcher: Set correct button active on scroll
    
    Presently a page scroll can only update between the top two buttons as active in the switcher. Which gets 
ineffectual with addition of more sub_views. This fix opens gate to add more relevant sub_views 
(Disks/Network/GPU under performance).

 src/graph-stack-switcher.vala | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)
---
diff --git a/src/graph-stack-switcher.vala b/src/graph-stack-switcher.vala
index 5319918..d0ced06 100644
--- a/src/graph-stack-switcher.vala
+++ b/src/graph-stack-switcher.vala
@@ -82,8 +82,14 @@ namespace Usage
         {
             Gtk.Allocation alloc;
 
-            this.sub_views[1].get_allocation(out alloc);
-            var button_number = (y < alloc.y) ? 0 : 1;
+            var button_number = 0;
+            for(int i = 1; i < buttons.length; i++)
+            {
+                this.sub_views[i].get_allocation(out alloc);
+                if(y < alloc.y)
+                    break;
+                button_number = i;
+            }
 
             buttons[button_number].set_active(true);
         }