Use SkMatrix44 for the underlying implementation of ui::Transform

ui/gfx/transform.h

Index: ui/gfx/transform.h
diff --git a/ui/gfx/transform.h b/ui/gfx/transform.h
index c3f86ef04f821e4743cd21634bd3a09a0e895495..1482fb7e9c85c1e1b4996e0ae1ba33e5caa2d09e 100644
--- a/ui/gfx/transform.h
+++ b/ui/gfx/transform.h
@@ -6,25 +6,26 @@
 #define UI_GFX_TRANSFORM_H_
 #pragma once
 
-#include "base/basictypes.h"
-#include "base/compiler_specific.h"
-#include "third_party/skia/include/core/SkMatrix.h"
+#include "third_party/skia/include/utils/SkMatrix44.h"
 
 namespace gfx {
-class Point;
 class Rect;
+class Point;
+class Point3f;
 }
 
 namespace ui {
 
-// 3x3 transformation matrix. Transform is cheap and explicitly allows
+// 4x4 transformation matrix. Transform is cheap and explicitly allows
 // copy/assign.
-// TODO: make this a 4x4.
 class Transform {
  public:
   Transform();
   ~Transform();
 
+  bool operator==(const Transform& rhs) const;
+  bool operator!=(const Transform& rhs) const;
+
   // NOTE: The 'Set' functions overwrite the previously set transformation
   // parameters. The 'Concat' functions apply a transformation (e.g. rotation,
   // scale, translate) on top of the existing transforms, instead of overwriting
@@ -57,44 +58,59 @@ class Transform {
   void ConcatTranslate(float x, float y);
 
   // Applies a transformation on the current transformation
-  // (i.e. 'this = this * transform;'). Returns true if the result can be
-  // represented.
-  bool PreconcatTransform(const Transform& transform);
+  // (i.e. 'this = this * transform;').
+  void PreconcatTransform(const Transform& transform);
 
   // Applies a transformation on the current transformation
-  // (i.e. 'this = transform * this;'). Returns true if the result can be
-  // represented.
-  bool ConcatTransform(const Transform& transform);
+  // (i.e. 'this = transform * this;').
+  void ConcatTransform(const Transform& transform);
 
   // Does the transformation change anything?
   bool HasChange() const;
 
   // Applies the transformation on the point. Returns true if the point is
   // transformed successfully.
-  bool TransformPoint(gfx::Point* point) const;
+  void TransformPoint(gfx::Point3f& point) const;
 
-  // Applies the reverse transformation on the point. Returns true if the point
-  // is transformed successfully.
-  bool TransformPointReverse(gfx::Point* point) const;
-
-  // Applies transformation on the rectangle. Returns true if the rectangle is
-  // transformed successfully.
-  bool TransformRect(gfx::Rect* rect) const;
-
-  // Applies the reverse transformation on the rectangle. Returns true if the
-  // rectangle is transformed successfully.
+  // Applies the transformation on the point. Returns true if the point is
+  // transformed successfully. Rounds the result to the nearest point.
+  void TransformPoint(gfx::Point& point) const;
+
+  // Applies the reverse transformation on the point. Returns true if the
+  // transformation can be inverted.
+  bool TransformPointReverse(gfx::Point3f& point) const;
+
+  // Applies the reverse transformation on the point. Returns true if the
+  // transformation can be inverted. Rounds the result to the nearest point.
+  bool TransformPointReverse(gfx::Point& point) const;
+
+  // Applies transformation on the rectangle. Returns true if the transformed
+  // rectangle was axis aligned. If it returns false, rect will be the
+  // smallest axis aligned bounding box containg the transformed rect.
+  void TransformRect(gfx::Rect* rect) const;
+
+  // Applies the reverse transformation on the rectangle. Returns true if
+  // the transformed rectangle was axis aligned. If it returns false,
+  // rect will be the smallest axis aligned bounding box containg the
+  // transformed rect.
   bool TransformRectReverse(gfx::Rect* rect) const;
 
   // Returns the underlying matrix.
-  const SkMatrix& matrix() const { return matrix_; }
-  SkMatrix& matrix() { return matrix_; }
+  const SkMatrix44& matrix() const { return matrix_; }
+  SkMatrix44& matrix() { return matrix_; }
 
  private:
-  SkMatrix matrix_;
+  void TransformPointInternal(const SkMatrix44& xform,
+                              gfx::Point& point) const;
+
+  void TransformPointInternal(const SkMatrix44& xform,
+                              gfx::Point3f& point) const;
+
+  SkMatrix44 matrix_;
 
   // copy/assign are allowed.
 };
 
-}  // namespace ui
+}// namespace ui
 
 #endif  // UI_GFX_TRANSFORM_H_