Add detection for rotation and flip overlay transforms

cc/base/math_util.h

 // Copyright 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.
 
 #ifndef CC_BASE_MATH_UTIL_H_
 #define CC_BASE_MATH_UTIL_H_
 
 #include <algorithm>
 #include <cmath>
 #include <vector>
@@ skipping 15 matching lines @@
 }
 }  // namespace base
 
 namespace gfx {
 class QuadF;
 class Rect;
 class RectF;
 class Transform;
 class Vector2dF;
 class Vector2d;
+class Vector3dF;
 }
 
 namespace cc {
 
 struct HomogeneousCoordinate {
   HomogeneousCoordinate(SkMScalar x, SkMScalar y, SkMScalar z, SkMScalar w) {
     vec[0] = x;
     vec[1] = y;
     vec[2] = z;
     vec[3] = w;
@@ skipping 187 matching lines @@
                                const gfx::Transform& transform,
                                base::trace_event::TracedValue* res);
   static void AddToTracedValue(const char* name,
                                const gfx::BoxF& box,
                                base::trace_event::TracedValue* res);
 
   // Returns a base::Value representation of the floating point value.
   // If the value is inf, returns max double/float representation.
   static double AsDoubleSafely(double value);
   static float AsFloatSafely(float value);
+
+  // Returns vector that x axis (1,0,0) transforms to under given transform

[danakj, 2015/05/12 23:32:15]

nit: period

[halliwell, 2015/05/13 00:49:50]

Done.

+  static gfx::Vector3dF GetXAxis(const gfx::Transform& transform);
+
+  // Returns vector that y axis (0,1,0) transforms to under given transform

[danakj, 2015/05/12 23:32:15]

dittonit

[halliwell, 2015/05/13 00:49:50]

Done.

+  static gfx::Vector3dF GetYAxis(const gfx::Transform& transform);
 };
 
 }  // namespace cc
 
 #endif  // CC_BASE_MATH_UTIL_H_