ui: Add methods to clamp Sizes, Points, and Vectors from above or below.

ui/gfx/point_base.h

Index: ui/gfx/point_base.h
diff --git a/ui/gfx/point_base.h b/ui/gfx/point_base.h
index acaefe17805df6bbc2aa241805175eedea6c6656..24ce5f2195eb46f7454fcf9caf612f5080d4328e 100644
--- a/ui/gfx/point_base.h
+++ b/ui/gfx/point_base.h
@@ -41,6 +41,16 @@ class UI_EXPORT PointBase {
     Offset(-other.x(), -other.y());
   }
 
+  void ClampFromAbove(const Class& other) {

[sky, 2012/11/09 18:23:12]

Is there some other name we could use for these that doesn't imply the
coordinates in a particular direction?

+    x_ = x_ <= other.x_ ? x_ : other.x_;
+    y_ = y_ <= other.y_ ? y_ : other.y_;
+  }
+
+  void ClampFromBelow(const Class& other) {
+    x_ = x_ >= other.x_ ? x_ : other.x_;
+    y_ = y_ >= other.y_ ? y_ : other.y_;
+  }
+
   Class Add(const VectorClass& other) const WARN_UNUSED_RESULT {
     const Class* orig = static_cast<const Class*>(this);
     Class copy = *orig;