cc: Convert non-const reference arguments to pointers.

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"
 
 namespace {
 const double kAngleEpsilon = 1e-4;
 }
 
 namespace cc {
 
 bool TransformOperation::IsIdentity() const {
   return matrix.IsIdentity();
 }
 
 static bool IsOperationIdentity(const TransformOperation* operation) {
   return !operation || operation->IsIdentity();
 }
 
 static bool ShareSameAxis(const TransformOperation* from,
                           const TransformOperation* to,
-                          double& axis_x, double& axis_y, double& axis_z,
-                          double& angle_from) {
+                          double* axis_x,
+                          double* axis_y,
+                          double* axis_z,
+                          double* angle_from) {
   if (IsOperationIdentity(from) && IsOperationIdentity(to))
     return false;
 
   if (IsOperationIdentity(from) && !IsOperationIdentity(to)) {
-    axis_x = to->rotate.axis.x;
-    axis_y = to->rotate.axis.y;
-    axis_z = to->rotate.axis.z;
-    angle_from = 0;
+    *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)) {
-    axis_x = from->rotate.axis.x;
-    axis_y = from->rotate.axis.y;
-    axis_z = from->rotate.axis.z;
-    angle_from = from->rotate.angle;
+    *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;
   }
 
   double 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;
   double other_length_2 = to->rotate.axis.x * to->rotate.axis.x +
                           to->rotate.axis.y * to->rotate.axis.y +
                           to->rotate.axis.z * to->rotate.axis.z;
 
   if (length_2 <= kAngleEpsilon || other_length_2 <= kAngleEpsilon)
     return false;
 
   double dot = to->rotate.axis.x * from->rotate.axis.x +
                to->rotate.axis.y * from->rotate.axis.y +
                to->rotate.axis.z * from->rotate.axis.z;
   double error = std::fabs(1.0 - (dot * dot) / (length_2 * other_length_2));
   bool result = error < kAngleEpsilon;
   if (result) {
-    axis_x = to->rotate.axis.x;
-    axis_y = to->rotate.axis.y;
-    axis_z = to->rotate.axis.z;
+    *axis_x = to->rotate.axis.x;
+    *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;
+    *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) {
+    gfx::Transform* result) {
   if (IsOperationIdentity(from) && IsOperationIdentity(to))
     return true;
 
   TransformOperation::Type interpolation_type =
       TransformOperation::TransformOperationIdentity;
   if (IsOperationIdentity(to))
     interpolation_type = from->type;
   else
     interpolation_type = to->type;
 
   switch (interpolation_type) {
   case TransformOperation::TransformOperationTranslate: {
     double from_x = IsOperationIdentity(from) ? 0 : from->translate.x;
     double from_y = IsOperationIdentity(from) ? 0 : from->translate.y;
     double from_z = IsOperationIdentity(from) ? 0 : from->translate.z;
     double to_x = IsOperationIdentity(to) ? 0 : to->translate.x;
     double to_y = IsOperationIdentity(to) ? 0 : to->translate.y;
     double to_z = IsOperationIdentity(to) ? 0 : to->translate.z;
-    result.Translate3d(BlendDoubles(from_x, to_x, progress),
-                       BlendDoubles(from_y, to_y, progress),
-                       BlendDoubles(from_z, to_z, progress));
+    result->Translate3d(BlendDoubles(from_x, to_x, progress),
+                        BlendDoubles(from_y, to_y, progress),
+                        BlendDoubles(from_z, to_z, progress));
     break;
   }
   case TransformOperation::TransformOperationRotate: {
     double axis_x = 0;
     double axis_y = 0;
     double axis_z = 1;
     double from_angle = 0;
     double to_angle = IsOperationIdentity(to) ? 0 : to->rotate.angle;
-    if (ShareSameAxis(from, to, axis_x, axis_y, axis_z, from_angle)) {
-      result.RotateAbout(gfx::Vector3dF(axis_x, axis_y, axis_z),
-                         BlendDoubles(from_angle, to_angle, progress));
-    } else {
+    if (ShareSameAxis(from, to, &axis_x, &axis_y, &axis_z, &from_angle))
+      result->RotateAbout(gfx::Vector3dF(axis_x, axis_y, axis_z),
+                          BlendDoubles(from_angle, to_angle, progress));
+    else {
       gfx::Transform to_matrix;
       if (!IsOperationIdentity(to))
         to_matrix = to->matrix;
       gfx::Transform from_matrix;
       if (!IsOperationIdentity(from))
         from_matrix = from->matrix;
-      result = to_matrix;
-      if (!result.Blend(from_matrix, progress))
+      *result = to_matrix;
+      if (!result->Blend(from_matrix, progress))
         return false;
     }
     break;
   }
   case TransformOperation::TransformOperationScale: {
     double from_x = IsOperationIdentity(from) ? 1 : from->scale.x;
     double from_y = IsOperationIdentity(from) ? 1 : from->scale.y;
     double from_z = IsOperationIdentity(from) ? 1 : from->scale.z;
     double to_x = IsOperationIdentity(to) ? 1 : to->scale.x;
     double to_y = IsOperationIdentity(to) ? 1 : to->scale.y;
     double to_z = IsOperationIdentity(to) ? 1 : to->scale.z;
-    result.Scale3d(BlendDoubles(from_x, to_x, progress),
-                   BlendDoubles(from_y, to_y, progress),
-                   BlendDoubles(from_z, to_z, progress));
+    result->Scale3d(BlendDoubles(from_x, to_x, progress),
+                    BlendDoubles(from_y, to_y, progress),
+                    BlendDoubles(from_z, to_z, progress));
     break;
   }
   case TransformOperation::TransformOperationSkew: {
     double from_x = IsOperationIdentity(from) ? 0 : from->skew.x;
     double from_y = IsOperationIdentity(from) ? 0 : from->skew.y;
     double to_x = IsOperationIdentity(to) ? 0 : to->skew.x;
     double to_y = IsOperationIdentity(to) ? 0 : to->skew.y;
-    result.SkewX(BlendDoubles(from_x, to_x, progress));
-    result.SkewY(BlendDoubles(from_y, to_y, progress));
+    result->SkewX(BlendDoubles(from_x, to_x, progress));
+    result->SkewY(BlendDoubles(from_y, to_y, progress));
     break;
   }
   case TransformOperation::TransformOperationPerspective: {
     double from_perspective_depth = IsOperationIdentity(from) ?
         std::numeric_limits<double>::max() : from->perspective_depth;
     double to_perspective_depth = IsOperationIdentity(to) ?
         std::numeric_limits<double>::max() : to->perspective_depth;
-    result.ApplyPerspectiveDepth(
+    result->ApplyPerspectiveDepth(
         BlendDoubles(from_perspective_depth, to_perspective_depth, progress));
     break;
   }
   case TransformOperation::TransformOperationMatrix: {
     gfx::Transform to_matrix;
     if (!IsOperationIdentity(to))
       to_matrix = to->matrix;
     gfx::Transform from_matrix;
     if (!IsOperationIdentity(from))
       from_matrix = from->matrix;
-    result = to_matrix;
-    if (!result.Blend(from_matrix, progress))
+    *result = to_matrix;
+    if (!result->Blend(from_matrix, progress))
       return false;
     break;
   }
   case TransformOperation::TransformOperationIdentity:
     // Do nothing.
     break;
   }
 
   return true;
 }
 
 }  // namespace cc