views::Border: Added CreateRoundedRectBorder.

This draws a rounded rectangle, as opposed to CreateSolidBorder which
draws square corners.

Also adds a floating-point overload to Canvas::DrawRoundRect.

BUG=548552,553726

Review URL: https://codereview.chromium.org/1428623005

Cr-Commit-Position: refs/heads/master@{#358767}
diff --git a/ui/gfx/canvas.h b/ui/gfx/canvas.h
index fd6e3c71..d154962 100644
--- a/ui/gfx/canvas.h
+++ b/ui/gfx/canvas.h
@@ -20,6 +20,7 @@
 namespace gfx {
 
 class Rect;
+class RectF;
 class FontList;
 class Point;
 class Size;
@@ -248,9 +249,14 @@
                   const SkPaint& paint);
 
   // Draws the given rectangle with rounded corners of |radius| using the
-  // given |paint| parameters.
+  // given |paint| parameters. DEPRECATED in favor of the RectF version below.
+  // TODO(mgiuca): Remove this (http://crbug.com/553726).
   void DrawRoundRect(const Rect& rect, int radius, const SkPaint& paint);
 
+  // Draws the given rectangle with rounded corners of |radius| using the
+  // given |paint| parameters.
+  void DrawRoundRect(const RectF& rect, float radius, const SkPaint& paint);
+
   // Draws the given path using the given |paint| parameters.
   void DrawPath(const SkPath& path, const SkPaint& paint);