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

ui/gfx/transform.cc

 // 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.
 
 // MSVC++ requires this to be set before any other includes to get M_PI.
 #define _USE_MATH_DEFINES
 
 #include "ui/gfx/transform.h"
 
 #include <cmath>
@@ skipping 347 matching lines @@
     return false;
 
   const SkMatrix& matrix = inverse;
   SkRect src = RectFToSkRect(*rect);
   matrix.mapRect(&src);
   *rect = SkRectToRectF(src);
   return true;
 }
 
 bool Transform::Blend(const Transform& from, double progress) {
-  if (progress <= 0.0) {
-    *this = from;
-    return true;
-  }
-
-  if (progress >= 1.0)
-    return true;
-

[ajuma, 2013/06/01 14:54:12]

Please add a gfx::Transform unit test for this that uses a value of progress not
in [0, 1]. (This is already indirectly tested by the TransformOperation unit
tests you added, but I think we should also directly test this.)

   DecomposedTransform to_decomp;
   DecomposedTransform from_decomp;
   if (!DecomposeTransform(&to_decomp, *this) ||
       !DecomposeTransform(&from_decomp, from))
     return false;
 
   if (!BlendDecomposedTransforms(&to_decomp, to_decomp, from_decomp, progress))
     return false;
 
   matrix_ = ComposeTransform(to_decomp).matrix();
@@ skipping 56 matching lines @@
       matrix_.getDouble(2, 1),
       matrix_.getDouble(2, 2),
       matrix_.getDouble(2, 3),
       matrix_.getDouble(3, 0),
       matrix_.getDouble(3, 1),
       matrix_.getDouble(3, 2),
       matrix_.getDouble(3, 3));
 }
 
 }  // namespace gfx