[ash-md] Makes Wi-Fi header row sticky when network list is scrolled

ui/views/layout/box_layout.cc

Index: ui/views/layout/box_layout.cc
diff --git a/ui/views/layout/box_layout.cc b/ui/views/layout/box_layout.cc
index f81fd68e3cbd6883abf200a59b64fbc39ebfe3bd..63a7faf290adec0593d64c5a72ce793da07b5229 100644
--- a/ui/views/layout/box_layout.cc
+++ b/ui/views/layout/box_layout.cc
@@ -103,49 +103,8 @@ void BoxLayout::Layout(View* host) {
   int main_position = MainAxisPosition(child_area);
   int total_padding = 0;
   int current_flex = 0;
-  for (int i = 0; i < host->child_count(); ++i) {
-    View* child = host->child_at(i);
-    if (!child->visible())
-      continue;
-
-    // Calculate cross axis size.
-    gfx::Rect bounds(child_area);
-    SetMainAxisPosition(main_position, &bounds);
-    if (cross_axis_alignment_ != CROSS_AXIS_ALIGNMENT_STRETCH) {
-      int free_space = CrossAxisSize(bounds) - CrossAxisSizeForView(child);
-      int position = CrossAxisPosition(bounds);
-      if (cross_axis_alignment_ == CROSS_AXIS_ALIGNMENT_CENTER) {
-        position += free_space / 2;
-      } else if (cross_axis_alignment_ == CROSS_AXIS_ALIGNMENT_END) {
-        position += free_space;
-      }
-      SetCrossAxisPosition(position, &bounds);
-      SetCrossAxisSize(CrossAxisSizeForView(child), &bounds);
-    }
-
-    // Calculate flex padding.
-    int current_padding = 0;
-    if (GetFlexForView(child) > 0) {
-      current_flex += GetFlexForView(child);
-      int quot = (main_free_space * current_flex) / flex_sum;
-      int rem = (main_free_space * current_flex) % flex_sum;
-      current_padding = quot - total_padding;
-      // Use the current remainder to round to the nearest pixel.
-      if (std::abs(rem) * 2 >= flex_sum)
-        current_padding += main_free_space > 0 ? 1 : -1;
-      total_padding += current_padding;
-    }
-
-    // Set main axis size.
-    int child_main_axis_size = MainAxisSizeForView(child, child_area.width());
-    SetMainAxisSize(child_main_axis_size + current_padding, &bounds);
-    if (MainAxisSize(bounds) > 0 || GetFlexForView(child) > 0)
-      main_position += MainAxisSize(bounds) + between_child_spacing_;
-
-    // Clamp child view bounds to |child_area|.
-    bounds.Intersect(child_area);
-    child->SetBoundsRect(bounds);
-  }
+  LayoutChildren(host, child_area, main_free_space, flex_sum, main_position,
+                 current_flex, &total_padding);
 
   // Flex views should have grown/shrunk to consume all free space.
   if (flex_sum)
@@ -176,6 +135,68 @@ int BoxLayout::GetPreferredHeightForWidth(const View* host, int width) const {
   return GetPreferredSizeForChildWidth(host, child_width).height();
 }
 
+void BoxLayout::LayoutChild(View* child,
+                            const gfx::Rect& child_area,
+                            int main_free_space,
+                            int flex_sum,
+                            int* main_position,
+                            int* current_flex,
+                            int* total_padding) {
+  // Calculate cross axis size.
+  gfx::Rect bounds(child_area);
+  SetMainAxisPosition(*main_position, &bounds);
+  if (cross_axis_alignment_ != CROSS_AXIS_ALIGNMENT_STRETCH) {
+    int free_space = CrossAxisSize(bounds) - CrossAxisSizeForView(child);
+    int position = CrossAxisPosition(bounds);
+    if (cross_axis_alignment_ == CROSS_AXIS_ALIGNMENT_CENTER) {
+      position += free_space / 2;
+    } else if (cross_axis_alignment_ == CROSS_AXIS_ALIGNMENT_END) {
+      position += free_space;
+    }
+    SetCrossAxisPosition(position, &bounds);
+    SetCrossAxisSize(CrossAxisSizeForView(child), &bounds);
+  }
+
+  // Calculate flex padding.
+  int current_padding = 0;
+  if (GetFlexForView(child) > 0) {
+    *current_flex += GetFlexForView(child);
+    int quot = (main_free_space * *current_flex) / flex_sum;
+    int rem = (main_free_space * *current_flex) % flex_sum;
+    current_padding = quot - *total_padding;
+    // Use the current remainder to round to the nearest pixel.
+    if (std::abs(rem) * 2 >= flex_sum)
+      current_padding += main_free_space > 0 ? 1 : -1;
+    *total_padding += current_padding;
+  }
+
+  // Set main axis size.
+  int child_main_axis_size = MainAxisSizeForView(child, child_area.width());
+  SetMainAxisSize(child_main_axis_size + current_padding, &bounds);
+  if (MainAxisSize(bounds) > 0 || GetFlexForView(child) > 0)
+    *main_position += MainAxisSize(bounds) + between_child_spacing_;
+
+  // Clamp child view bounds to |child_area|.
+  bounds.Intersect(child_area);
+  child->SetBoundsRect(bounds);
+}
+
+void BoxLayout::LayoutChildren(View* host,
+                               const gfx::Rect& child_area,
+                               int main_free_space,
+                               int flex_sum,
+                               int main_position,
+                               int current_flex,
+                               int* total_padding) {
+  for (int i = 0; i < host->child_count(); ++i) {
+    View* child = host->child_at(i);
+    if (!child->visible())
+      continue;
+    LayoutChild(child, child_area, main_free_space, flex_sum, &main_position,
+                &current_flex, total_padding);
+  }
+}
+
 void BoxLayout::Installed(View* host) {
   DCHECK(!host_);
   host_ = host;