TransformOperations should be able to blend outside the range [0, 1]

cc/animation/transform_operation.cc

 // Copyright 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 <cmath>
 #include <limits>
 
 #include "cc/animation/transform_operation.h"
 #include "ui/gfx/vector3d_f.h"
 
@@ skipping 56 matching lines @@
     *axis_y = to->rotate.axis.y;
     *axis_z = to->rotate.axis.z;
     // If the axes are pointing in opposite directions, we need to reverse
     // the angle.
     *angle_from = dot > 0 ? from->rotate.angle : -from->rotate.angle;
   }
   return result;
 }
 
 static double BlendDoubles(double from, double to, double progress) {
-  if (progress <= 0.0)
-    return from;
-
-  if (progress >= 1.0)
-    return to;
-
   return from * (1 - progress) + to * progress;
 }
 
 bool TransformOperation::BlendTransformOperations(
     const TransformOperation* from,
     const TransformOperation* to,
     double progress,
     gfx::Transform* result) {
   if (IsOperationIdentity(from) && IsOperationIdentity(to))
     return true;
@@ skipping 84 matching lines @@
   }
   case TransformOperation::TransformOperationIdentity:
     // Do nothing.
     break;
   }
 
   return true;
 }
 
 }  // namespace cc