Update shelf spacing in Chrome OS according to the MD specs

ash/system/status_area_widget_delegate.cc

Index: ash/system/status_area_widget_delegate.cc
diff --git a/ash/system/status_area_widget_delegate.cc b/ash/system/status_area_widget_delegate.cc
index 0c1b574fad32f209c871a37bb8762d3af4a0704a..ad153791b1b60c2864b20c4c1645ea758ddfe9dd 100644
--- a/ash/system/status_area_widget_delegate.cc
+++ b/ash/system/status_area_widget_delegate.cc
@@ -6,6 +6,8 @@
 
 #include "ash/ash_export.h"
 #include "ash/ash_switches.h"
+#include "ash/common/material_design/material_design_controller.h"
+#include "ash/common/shelf/shelf_constants.h"
 #include "ash/common/shelf/wm_shelf_util.h"
 #include "ash/common/shell_window_ids.h"
 #include "ash/common/system/tray/tray_constants.h"
@@ -20,6 +22,7 @@
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/image/image.h"
 #include "ui/views/accessible_pane_view.h"
+#include "ui/views/border.h"
 #include "ui/views/layout/grid_layout.h"
 #include "ui/views/widget/widget.h"
 
@@ -112,15 +115,26 @@ void StatusAreaWidgetDelegate::UpdateLayout() {
   views::GridLayout* layout = new views::GridLayout(this);
   SetLayoutManager(layout);
 
+  // Update tray border based on layout.
+  bool is_child_on_edge = true;
+  for (int c = 0; c < child_count(); ++c) {
+    views::View* child = child_at(c);
+    if (!child->visible())
+      continue;
+    SetBorderOnChild(child, is_child_on_edge);
+    is_child_on_edge = false;
+  }
+
   views::ColumnSet* columns = layout->AddColumnSet(0);
+
   if (IsHorizontalAlignment(alignment_)) {
     bool is_first_visible_child = true;
-    for (int c = 0; c < child_count(); ++c) {
+    for (int c = child_count() - 1; c >= 0; --c) {
       views::View* child = child_at(c);
       if (!child->visible())
         continue;
       if (!is_first_visible_child)
-        columns->AddPaddingColumn(0, kTraySpacing);
+        columns->AddPaddingColumn(0, GetTrayConstant(TRAY_SPACING));
       is_first_visible_child = false;
       columns->AddColumn(views::GridLayout::CENTER, views::GridLayout::FILL,
                          0, /* resize percent */
@@ -142,7 +156,7 @@ void StatusAreaWidgetDelegate::UpdateLayout() {
       if (!child->visible())
         continue;
       if (!is_first_visible_child)
-        layout->AddPaddingRow(0, kTraySpacing);
+        layout->AddPaddingRow(0, GetTrayConstant(TRAY_SPACING));
       is_first_visible_child = false;
       layout->StartRow(0, 0);
       layout->AddView(child);
@@ -171,4 +185,63 @@ void StatusAreaWidgetDelegate::UpdateWidgetSize() {
     GetWidget()->SetSize(GetPreferredSize());
 }
 
+void StatusAreaWidgetDelegate::SetBorderOnChild(views::View* child,
+                                                bool extend_border_to_edge) {
+  int top_edge, left_edge, bottom_edge, right_edge;
+  // Tray views are laid out right-to-left or bottom-to-top
+  if (MaterialDesignController::IsShelfMaterial()) {
+    if (extend_border_to_edge) {
+      if (IsHorizontalAlignment(alignment_)) {
+        top_edge = (GetShelfConstant(SHELF_SIZE) - kShelfItemHeight) / 2;
+        left_edge = 0;
+        bottom_edge = (GetShelfConstant(SHELF_SIZE) - kShelfItemHeight) / 2;
+        right_edge = GetTrayConstant(TRAY_PADDING_FROM_EDGE_OF_SHELF);
+      } else {
+        top_edge = 0;
+        left_edge = (GetShelfConstant(SHELF_SIZE) - kShelfItemHeight) / 2;
+        bottom_edge = GetTrayConstant(TRAY_PADDING_FROM_EDGE_OF_SHELF);
+        right_edge = (GetShelfConstant(SHELF_SIZE) - kShelfItemHeight) / 2;
+      }
+    } else {
+      if (IsHorizontalAlignment(alignment_)) {
+        top_edge = (GetShelfConstant(SHELF_SIZE) - kShelfItemHeight) / 2;
+        left_edge = 0;
+        bottom_edge = (GetShelfConstant(SHELF_SIZE) - kShelfItemHeight) / 2;
+        right_edge = 0;
+      } else {
+        top_edge = 0;
+        left_edge = (GetShelfConstant(SHELF_SIZE) - kShelfItemHeight) / 2;
+        bottom_edge = 0;
+        right_edge = (GetShelfConstant(SHELF_SIZE) - kShelfItemHeight) / 2;
+      }
+    }
+  } else {
+    bool on_edge = (child == child_at(0));
+    if (IsHorizontalAlignment(alignment_)) {
+      top_edge = kShelfItemInset;
+      left_edge = 0;
+      bottom_edge =
+          GetShelfConstant(SHELF_SIZE) - kShelfItemInset - kShelfItemHeight;
+      right_edge =
+          on_edge ? GetTrayConstant(TRAY_PADDING_FROM_EDGE_OF_SHELF) : 0;
+    } else if (alignment_ == SHELF_ALIGNMENT_LEFT) {
+      top_edge = 0;
+      left_edge =
+          GetShelfConstant(SHELF_SIZE) - kShelfItemInset - kShelfItemHeight;
+      bottom_edge =
+          on_edge ? GetTrayConstant(TRAY_PADDING_FROM_EDGE_OF_SHELF) : 0;
+      right_edge = kShelfItemInset;
+    } else {  // SHELF_ALIGNMENT_RIGHT
+      top_edge = 0;
+      left_edge = kShelfItemInset;
+      bottom_edge =
+          on_edge ? GetTrayConstant(TRAY_PADDING_FROM_EDGE_OF_SHELF) : 0;
+      right_edge =
+          GetShelfConstant(SHELF_SIZE) - kShelfItemInset - kShelfItemHeight;
+    }
+  }
+  child->SetBorder(views::Border::CreateEmptyBorder(top_edge, left_edge,
+                                                    bottom_edge, right_edge));
+}
+
 }  // namespace ash