Cros: Use floating values for obtaining icon bounds

Because we are scaling the icon bounds to animate long press gestures,
some values might be incorrectly rounded.
Change the method that calculates the bounds with scale to use floating
values and then Round the resulting rect to adapt to grid layer.
Also, include the icon shadows for scaling.

Bug: 1050730
Change-Id: Ief19fcf0d2894f570a77047f8209e53eeb461b73
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2086317Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Toni Baržić <tbarzic@chromium.org>
Commit-Queue: Ana Salazar <anasalazar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#748337}

ash/shelf/shelf_app_button.cc

@@ -609,21 +609,20 @@ bool ShelfAppButton::OnMouseDragged(const ui::MouseEvent& event) {
 }
 
 gfx::Rect ShelfAppButton::GetIconViewBounds(float icon_scale) {
-  int icon_size = ShelfConfig::Get()->button_icon_size() * icon_scale;
-  // TODO: Find out why there is an extra pixel of padding between each item
-  // and the inner side of the shelf.
-  // clang-format off
-  int icon_padding = (ShelfConfig::Get()->hotseat_size() - icon_size) / 2;
-  // clang-format on
+  const float icon_size = ShelfConfig::Get()->button_icon_size() * icon_scale;
+  const float icon_padding =
+      (ShelfConfig::Get()->hotseat_size() - icon_size) / 2;
 
   const gfx::Rect button_bounds(GetContentsBounds());
-  Shelf* shelf = shelf_view_->shelf();
+  const Shelf* shelf = shelf_view_->shelf();
   const bool is_horizontal_shelf = shelf->IsHorizontalAlignment();
-  int x_offset = is_horizontal_shelf ? 0 : icon_padding;
-  int y_offset = is_horizontal_shelf ? icon_padding : 0;
+  float x_offset = is_horizontal_shelf ? 0 : icon_padding;
+  float y_offset = is_horizontal_shelf ? icon_padding : 0;
 
-  int icon_width = std::min(icon_size, button_bounds.width() - x_offset);
-  int icon_height = std::min(icon_size, button_bounds.height() - y_offset);
+  const float icon_width =
+      std::min(icon_size, button_bounds.width() - x_offset);
+  const float icon_height =
+      std::min(icon_size, button_bounds.height() - y_offset);
 
   // If on the left or top 'invert' the inset so the constant gap is on
   // the interior (towards the center of display) edge of the shelf.
@@ -632,21 +631,15 @@ gfx::Rect ShelfAppButton::GetIconViewBounds(float icon_scale) {
 
   // Expand bounds to include shadows.
   gfx::Insets insets_shadows = gfx::ShadowValue::GetMargin(icon_shadows_);
+  // insets_shadows = insets_shadows.Scale(icon_scale);
   // Center icon with respect to the secondary axis.
-  if (is_horizontal_shelf) {
-    x_offset =
-        std::max(0, button_bounds.width() - icon_width + insets_shadows.left() -
-                        insets_shadows.right() + 1) /
-        2;
-  } else {
-    y_offset =
-        std::max(0, button_bounds.height() - icon_height +
-                        insets_shadows.top() - insets_shadows.bottom() + 1) /
-        2;
-  }
-  gfx::Rect icon_view_bounds =
-      gfx::Rect(button_bounds.x() + x_offset, button_bounds.y() + y_offset,
-                icon_width, icon_height);
+  if (is_horizontal_shelf)
+    x_offset = std::max(0.0f, button_bounds.width() - icon_width + 1) / 2;
+  else
+    y_offset = std::max(0.0f, button_bounds.height() - icon_height) / 2;
+  gfx::RectF icon_view_bounds =
+      gfx::RectF(button_bounds.x() + x_offset, button_bounds.y() + y_offset,
+                 icon_width, icon_height);
 
   icon_view_bounds.Inset(insets_shadows);
   // Icon size has been incorrect when running
@@ -654,7 +647,7 @@ gfx::Rect ShelfAppButton::GetIconViewBounds(float icon_scale) {
   // http://crbug.com/234854.
   DCHECK_LE(icon_width, icon_size);
   DCHECK_LE(icon_height, icon_size);
-  return icon_view_bounds;
+  return gfx::ToRoundedRect(icon_view_bounds);
 }
 
 void ShelfAppButton::Layout() {