Stabilize empty rect handling in EnclosingRect.

ui/gfx/geometry/rect_unittest.cc

 // Copyright (c) 2013 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.
 
 #include <limits>
 
 #include <stddef.h>
 
 #include "base/macros.h"
 #include "build/build_config.h"
@@ skipping 503 matching lines @@
     EXPECT_FLOAT_AND_NAN_EQ(r2.y(), enclosed.y());
     EXPECT_FLOAT_AND_NAN_EQ(r2.width(), enclosed.width());
     EXPECT_FLOAT_AND_NAN_EQ(r2.height(), enclosed.height());
   }
 }
 
 TEST(RectTest, ToEnclosingRect) {
   static const int max_int = std::numeric_limits<int>::max();
   static const int min_int = std::numeric_limits<int>::min();
   static const float max_float = std::numeric_limits<float>::max();
+  static const float epsilon_float = std::numeric_limits<float>::epsilon();
   static const struct Test {
     float x1; // source
     float y1;
     float w1;
     float h1;
     int x2; // target
     int y2;
     int w2;
     int h2;
   } tests[] = {
       {0.0f, 0.0f, 0.0f, 0.0f, 0, 0, 0, 0},
       {5.5f, 5.5f, 0.0f, 0.0f, 5, 5, 0, 0},
+      {3.5f, 2.5f, epsilon_float, -0.0f, 3, 2, 0, 0},
       {-1.5f, -1.5f, 3.0f, 3.0f, -2, -2, 4, 4},
       {-1.5f, -1.5f, 3.5f, 3.5f, -2, -2, 4, 4},
       {max_float, max_float, 2.0f, 2.0f, max_int, max_int, 0, 0},
       {0.0f, 0.0f, max_float, max_float, 0, 0, max_int, max_int},
       {20000.5f, 20000.5f, 0.5f, 0.5f, 20000, 20000, 1, 1},
       {static_cast<float>(min_int), static_cast<float>(min_int), max_int * 2.f,
        max_int * 2.f, min_int, min_int, max_int, max_int},
       {static_cast<float>(max_int), static_cast<float>(max_int),
        static_cast<float>(max_int), static_cast<float>(max_int), max_int,
        max_int, 0, 0},
@@ skipping 544 matching lines @@
 
   Rect min_rect(min_int, min_int, max_int, max_int);
   // Min rect can't be scaled up any further in any dimension.
   EXPECT_EQ(ScaleToEnclosingRectSafe(min_rect, 2, 3.5), min_rect);
   EXPECT_EQ(ScaleToEnclosingRectSafe(min_rect, max_int, max_int), min_rect);
   // Min rect scaled by min is an empty rect at (max, max)
   EXPECT_EQ(ScaleToEnclosingRectSafe(min_rect, min_int, min_int), max_rect);
 }
 
 }  // namespace gfx