Page zoom improvements

content/public/common/page_zoom.cc

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.

[jam, 2011/11/21 22:20:54]

nit: sorry i should have said this earlier, wasn't sure if you were going to
have a cc file here after the comments. if you are, please move this to
content/common/page_zoom.cc. we only leave cc files in content/public that have
constructor/destructors etc

[csilv, 2011/11/22 00:10:59]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <cmath>
+
+#include "content/public/common/page_zoom.h"
+
+namespace content {
+
+const double kMinimumZoomFactor = 0.25;
+const double kMaximumZoomFactor = 5.0;
+
+bool ZoomValuesEqual(double value_a, double value_b) {
+  // Epsilon value for comparing two floating-point zoom values. We don't use
+  // std::numeric_limits<> because it is too precise for zoom values. Zoom
+  // values lose precision due to factor/level conversions. A value of 0.001
+  // is precise enough for zoom value comparisons.
+  const double epsilon = 0.001;
+
+  return (std::fabs(value_a - value_b) <= epsilon);
+}
+
+}  // namespace content
+