gfx: Make conversions from gfx::Point to PointF explicit.

ui/gfx/geometry/point_f.h

Index: ui/gfx/geometry/point_f.h
diff --git a/ui/gfx/geometry/point_f.h b/ui/gfx/geometry/point_f.h
index f900c1ceae727cf408afff98b81e4d30ae3ae5ad..d3a99f149c9f4547149da0822eddb60e7a5694f7 100644
--- a/ui/gfx/geometry/point_f.h
+++ b/ui/gfx/geometry/point_f.h
@@ -8,6 +8,7 @@
 #include <iosfwd>
 #include <string>
 
+#include "ui/gfx/geometry/point.h"
 #include "ui/gfx/geometry/vector2d_f.h"
 #include "ui/gfx/gfx_export.h"
 
@@ -20,6 +21,9 @@ class GFX_EXPORT PointF {
   PointF(float x, float y) : x_(x), y_(y) {}
   ~PointF() {}
 
+  explicit PointF(const Point& p)
+      : PointF(static_cast<float>(p.x()), static_cast<float>(p.y())) {}
+
   float x() const { return x_; }
   float y() const { return y_; }
   void set_x(float x) { x_ = x; }