Add BoxF::ExpandTo

ui/gfx/box_f.cc

Index: ui/gfx/box_f.cc
diff --git a/ui/gfx/box_f.cc b/ui/gfx/box_f.cc
index efb579671457c9d78d3dbac1630207559ebd3d2a..cc6a1eef2314c3e443e9fea744673de39cc616d6 100644
--- a/ui/gfx/box_f.cc
+++ b/ui/gfx/box_f.cc
@@ -24,6 +24,20 @@ bool BoxF::IsEmpty() const {
          (height_ == 0 && depth_ == 0);
 }
 
+void BoxF::ExpandTo(const Point3F& min, const Point3F& max) {
+  float min_x = std::min(x(), min.x());

[danakj, 2013/10/01 14:23:44]

DCHECK() that min <= max please.

+  float min_y = std::min(y(), min.y());
+  float min_z = std::min(z(), min.z());
+  float max_x = std::max(right(), max.x());
+  float max_y = std::max(bottom(), max.y());
+  float max_z = std::max(front(), max.z());
+
+  origin_.SetPoint(min_x, min_y, min_z);
+  width_ = max_x - min_x;
+  height_ = max_y - min_y;
+  depth_ = max_z - min_z;
+}
+
 void BoxF::Union(const BoxF& box) {
   if (IsEmpty()) {
     *this = box;
@@ -32,17 +46,11 @@ void BoxF::Union(const BoxF& box) {
   if (box.IsEmpty())
     return;
 
-  float min_x = std::min(x(), box.x());
-  float min_y = std::min(y(), box.y());
-  float min_z = std::min(z(), box.z());
-  float max_x = std::max(right(), box.right());
-  float max_y = std::max(bottom(), box.bottom());
-  float max_z = std::max(front(), box.front());
+  ExpandTo(box.origin(), gfx::Point3F(box.right(), box.bottom(), box.front()));

[danakj, 2013/10/01 14:23:44]

What happens if |box| is entirely left/above |this|? That violates the
requirement for |min| and |max| on ExpandTo(min,max) doesn't it?

For instances, box = 0,0,0x5x5x5 and this = 20,20,20x5x5x5. You'll do
ExpandTo([20,20,20], [5,5,5])?

This case should be covered by the Union unit test, does it pass somehow?

+}
 
-  origin_.SetPoint(min_x, min_y, min_z);
-  width_ = max_x - min_x;
-  height_ = max_y - min_y;
-  depth_ = max_z - min_z;
+void BoxF::ExpandTo(const Point3F& point) {
+  ExpandTo(point, point);
 }
 
 BoxF UnionBoxes(const BoxF& a, const BoxF& b) {