Centered flood fill style ink drop ripples on mouse/touch points.

ui/gfx/geometry/rect.h

 // 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.
 
 // Defines a simple integer rectangle class.  The containment semantics
 // are array-like; that is, the coordinate (x, y) is considered to be
 // contained by the rectangle, but the coordinate (x + width, y) is not.
 // The class will happily let you create malformed rectangles (that is,
 // rectangles with negative width and/or height), but there will be assertions
 // in the operations (such as Contains()) to complain in this case.
@@ skipping 159 matching lines @@
   // Returns the manhattan distance from the rect to the point. If the point is
   // inside the rect, returns 0.
   int ManhattanDistanceToPoint(const Point& point) const;
 
   // Returns the manhattan distance between the contents of this rect and the
   // contents of the given rect. That is, if the intersection of the two rects
   // is non-empty then the function returns 0. If the rects share a side, it
   // returns the smallest non-zero value appropriate for int.
   int ManhattanInternalDistance(const Rect& rect) const;
 
+  // Returns the largest distance from |point| to the corners of |this|.
+  float MaxDistanceToCorners(const gfx::Point& point) const;

[sky, 2016/06/16 16:50:02]

This is very specialized and AFAICT only needed in one place. Can you move to
where it is used?

[bruthig, 2016/06/16 19:50:02]

Done.

+
   std::string ToString() const;
 
   bool ApproximatelyEqual(const Rect& rect, int tolerance) const;
 
  private:
   gfx::Point origin_;
   gfx::Size size_;
 };
 
 inline bool operator==(const Rect& lhs, const Rect& rhs) {
@@ skipping 80 matching lines @@
 }
 
 // This is declared here for use in gtest-based unit tests but is defined in
 // the gfx_test_support target. Depend on that to use this in your unit test.
 // This should not be used in production code - call ToString() instead.
 void PrintTo(const Rect& rect, ::std::ostream* os);
 
 }  // namespace gfx
 
 #endif  // UI_GFX_GEOMETRY_RECT_H_