Fix for bug where composited rotate3d should SLERP

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.
 
 // Needed on Windows to get |M_PI| from <cmath>
 #ifdef _WIN32
 #define _USE_MATH_DEFINES
 #endif
 
 #include <algorithm>
@@ skipping 23 matching lines @@
 
 static bool ShareSameAxis(const TransformOperation* from,
                           const TransformOperation* to,
                           SkMScalar* axis_x,
                           SkMScalar* axis_y,
                           SkMScalar* axis_z,
                           SkMScalar* angle_from) {
   if (IsOperationIdentity(from) && IsOperationIdentity(to))
     return false;
 
-  if (IsOperationIdentity(from) && !IsOperationIdentity(to)) {
+  if (!from && !IsOperationIdentity(to)) {
     *axis_x = to->rotate.axis.x;
     *axis_y = to->rotate.axis.y;
     *axis_z = to->rotate.axis.z;
     *angle_from = 0;
     return true;
   }
 
-  if (!IsOperationIdentity(from) && IsOperationIdentity(to)) {
+  if (!IsOperationIdentity(from) && !to) {
     *axis_x = from->rotate.axis.x;
     *axis_y = from->rotate.axis.y;
     *axis_z = from->rotate.axis.z;
     *angle_from = from->rotate.angle;
     return true;
   }
 
   SkMScalar length_2 = from->rotate.axis.x * from->rotate.axis.x +
                        from->rotate.axis.y * from->rotate.axis.y +
                        from->rotate.axis.z * from->rotate.axis.z;
@@ skipping 367 matching lines @@
       return true;
     }
     case TransformOperation::TRANSFORM_OPERATION_MATRIX:
       return false;
   }
   NOTREACHED();
   return false;
 }
 
 }  // namespace cc