make BoxLayout use and respect GetHeightForWidth().

ui/views/layout/box_layout.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/views/layout/box_layout.h"
 
-#include "ui/gfx/insets.h"
 #include "ui/gfx/rect.h"
 #include "ui/views/view.h"
 
 namespace views {
 
 BoxLayout::BoxLayout(BoxLayout::Orientation orientation,
                      int inside_border_horizontal_spacing,
                      int inside_border_vertical_spacing,
                      int between_child_spacing)
     : orientation_(orientation),
-      inside_border_horizontal_spacing_(inside_border_horizontal_spacing),
-      inside_border_vertical_spacing_(inside_border_vertical_spacing),
+      inside_border_insets_(inside_border_vertical_spacing,
+                            inside_border_horizontal_spacing,
+                            inside_border_vertical_spacing,
+                            inside_border_horizontal_spacing),
       between_child_spacing_(between_child_spacing),
       spread_blank_space_(false) {
 }
 
 BoxLayout::~BoxLayout() {
 }
 
 void BoxLayout::Layout(View* host) {
   gfx::Rect child_area(host->GetLocalBounds());
   child_area.Inset(host->GetInsets());
-  child_area.Inset(inside_border_horizontal_spacing_,
-                   inside_border_vertical_spacing_);
+  child_area.Inset(inside_border_insets_);
   int x = child_area.x();
   int y = child_area.y();
 
   int padding = 0;
   if (spread_blank_space_) {
     int total = 0;
     int visible = 0;
     for (int i = 0; i < host->child_count(); ++i) {
       View* child = host->child_at(i);
       if (!child->visible())
         continue;
-      if (orientation_ == kHorizontal)
+      if (orientation_ == kHorizontal) {
         total += child->GetPreferredSize().width() + between_child_spacing_;
-      else
-        total += child->GetPreferredSize().height() + between_child_spacing_;
+      } else {
+        total += child->GetHeightForWidth(child_area.width()) +
+            between_child_spacing_;
+      }
       ++visible;
     }
 
     if (visible) {
       total -= between_child_spacing_;
       if (orientation_ == kHorizontal)
         padding = (child_area.width() - total) / visible;
       else
         padding = (child_area.height() - total) / visible;
 
       if (padding < 0)
         padding = 0;
     }
   }
 
   for (int i = 0; i < host->child_count(); ++i) {
     View* child = host->child_at(i);
     if (child->visible()) {
       gfx::Rect bounds(x, y, child_area.width(), child_area.height());
-      gfx::Size size(child->GetPreferredSize());
       if (orientation_ == kHorizontal) {
-        bounds.set_width(size.width() + padding);
-        x += size.width() + between_child_spacing_ + padding;
+        bounds.set_width(child->GetPreferredSize().width() + padding);
+        x += bounds.width() + between_child_spacing_;
       } else {
-        bounds.set_height(size.height() + padding);
-        y += size.height() + between_child_spacing_ + padding;
+        bounds.set_height(child->GetHeightForWidth(bounds.width()) + padding);
+        y += bounds.height() + between_child_spacing_;
       }
       // Clamp child view bounds to |child_area|.
       bounds.Intersect(child_area);
       child->SetBoundsRect(bounds);
     }
   }
 }
 
 gfx::Size BoxLayout::GetPreferredSize(View* host) {
-  gfx::Rect bounds;
-  int position = 0;
-  for (int i = 0; i < host->child_count(); ++i) {
-    View* child = host->child_at(i);
-    if (child->visible()) {
-      gfx::Size size(child->GetPreferredSize());
-      if (orientation_ == kHorizontal) {
-        gfx::Rect child_bounds(position, 0, size.width(), size.height());
-        bounds.Union(child_bounds);
-        position += size.width();
-      } else {
-        gfx::Rect child_bounds(0, position, size.width(), size.height());
-        bounds.Union(child_bounds);
-        position += size.height();
-      }
-      position += between_child_spacing_;
+  // Calculate the child views' preferred width.
+  int width = 0;
+  if (orientation_ == kVertical) {
+    for (int i = 0; i < host->child_count(); ++i) {
+      View* child = host->child_at(i);
+      if (!child->visible())
+        continue;
+
+      width = std::max(width, child->GetPreferredSize().width());
     }
   }
+
+  return GetPreferredSizeForChildWidth(host, width);
+}
+
+int BoxLayout::GetPreferredHeightForWidth(View* host, int width) {
+  int child_width = width - NonChildSize(host).width();
+  return GetPreferredSizeForChildWidth(host, child_width).height();
+}
+
+gfx::Size BoxLayout::GetPreferredSizeForChildWidth(View* host,
+                                                   int child_area_width) {
+  gfx::Rect child_area_bounds;
+
+  if (orientation_ == kHorizontal) {
+    // Horizontal layouts ignore |child_area_width|, meaning they mimic the
+    // default behavior of GridLayout::GetPreferredHeightForWidth().
+    // TODO(estade): fix this if it ever becomes a problem.
+    int position = 0;
+    for (int i = 0; i < host->child_count(); ++i) {
+      View* child = host->child_at(i);
+      if (!child->visible())
+        continue;
+
+      gfx::Size size(child->GetPreferredSize());
+      gfx::Rect child_bounds(position, 0, size.width(), size.height());
+      child_area_bounds.Union(child_bounds);
+      position += size.width() + between_child_spacing_;
+    }
+  } else {
+    int height = 0;
+    for (int i = 0; i < host->child_count(); ++i) {
+      View* child = host->child_at(i);
+      if (!child->visible())
+        continue;
+
+      height += child->GetHeightForWidth(child_area_width);
+      if (i != 0)
+        height += between_child_spacing_;
+    }
+
+    child_area_bounds.set_width(child_area_width);
+    child_area_bounds.set_height(height);
+  }
+
+  gfx::Size non_child_size = NonChildSize(host);
+  return gfx::Size(child_area_bounds.width() + non_child_size.width(),
+                   child_area_bounds.height() + non_child_size.height());
+}
+
+gfx::Size BoxLayout::NonChildSize(View* host) {
   gfx::Insets insets(host->GetInsets());
-  return gfx::Size(
-      bounds.width() + insets.width() + 2 * inside_border_horizontal_spacing_,
-      bounds.height() + insets.height() + 2 * inside_border_vertical_spacing_);
+  return gfx::Size(insets.width() + inside_border_insets_.width(),
+                   insets.height() + inside_border_insets_.height());
 }
 
 } // namespace views