Magnifier: Move the cursor directly to the root window host.

ash/magnifier/magnifier_constants.h

 // Copyright (c) 2012 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.
 
 #ifndef ASH_MAGNIFIER_MAGNIFIER_CONSTANTS_H_
 #define ASH_MAGNIFIER_MAGNIFIER_CONSTANTS_H_
 
 namespace ash {
 
 // Note: Do not change these values; UMA and prefs depend on them.
 enum MagnifierType {
   MAGNIFIER_FULL    = 1,
   MAGNIFIER_PARTIAL = 2,
 };
 
 const int kMaxMagnifierType = 2;
 
 const MagnifierType kDefaultMagnifierType = MAGNIFIER_FULL;
 
+// Factor of magnification scale. For example, when this value is 1.189, scale
+// value will be changed x1.000, x1.189, x1.414, x1.681, x2.000, ...
+// Note: this value is 2.0 ^ (1 / 4).
+const float kMagnificationScaleFactor = 1.18920712f;
+
 }  // namespace ash
 
 #endif  // ASH_MAGNIFIER_MAGNIFIER_CONSTANTS_H_