CrOS AppList: Fix notification badge scaling jank

Using float instead of int for calculating the center point of the
notification badge allows for better positioning when the icon is
scaled up and down on long press.

Bug: 1131076
Change-Id: Ic5d41c1c94c941a984f34b3a41344160b10fceff
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2559312Reviewed-by: Toni Baržić <tbarzic@chromium.org>
Commit-Queue: Matthew Mourgos <mmourgos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#831079}

ash/app_list/views/app_list_item_view.cc

@@ -171,11 +171,11 @@ class AppListItemView::AppNotificationIndicatorView : public views::View {
     DCHECK_EQ(width(), height());
     const float dsf = canvas->UndoDeviceScaleFactor();
 
-    int radius = width() * kNotificationIndicatorWidthRatio / 2.0f;
-    int padding = width() * kNotificationIndicatorPaddingRatio;
+    float radius = width() * kNotificationIndicatorWidthRatio / 2.0f;
+    float padding = width() * kNotificationIndicatorPaddingRatio;
 
-    int center_x = width() - radius - padding;
-    int center_y = padding + radius;
+    float center_x = width() - radius - padding;
+    float center_y = padding + radius;
     gfx::PointF center = gfx::PointF(center_x, center_y);
     center.Scale(dsf);