Add gfx::ToRoundedInt safe conversion method from float to int.

ui/gfx/safe_integer_conversions.cc

Index: ui/gfx/safe_integer_conversions.cc
diff --git a/ui/gfx/safe_floor_ceil.cc b/ui/gfx/safe_integer_conversions.cc
similarity index 64%
rename from ui/gfx/safe_floor_ceil.cc
rename to ui/gfx/safe_integer_conversions.cc
index c8ac9e1c9e524e8508fcdb0ac3f0bc4a50e5cd14..e3543533e48d4e86a66bd094f907db26b211c875 100644
--- a/ui/gfx/safe_floor_ceil.cc
+++ b/ui/gfx/safe_integer_conversions.cc
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "ui/gfx/safe_integer_conversions.h"
+
 #include <cmath>
 #include <limits>
 
@@ -10,9 +12,9 @@ namespace gfx {
 int ClampToInt(float value) {
   if (value != value)
      return 0; // no int NaN.
-  if (value > std::numeric_limits<int>::max())
+  if (value >= std::numeric_limits<int>::max())
     return std::numeric_limits<int>::max();
-  if (value < std::numeric_limits<int>::min())
+  if (value <= std::numeric_limits<int>::min())
     return std::numeric_limits<int>::min();
   return static_cast<int>(value);
 }
@@ -25,5 +27,13 @@ int ToCeiledInt(float value) {
   return ClampToInt(std::ceil(value));
 }
 
-}  // namespace gfx
+int ToRoundedInt(float value) {
+  float rounded;
+  if (value >= 0.0f)
+    rounded = std::floor(value + 0.5f);
+  else
+    rounded = std::ceil(value - 0.5f);
+  return ClampToInt(rounded);
+}
 
+}  // namespace gfx