Hit test on the layer tree rather than the RSLL

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>
 
@@ skipping 126 matching lines @@
                               bool* clipped);
   static gfx::Point3F MapPoint(const gfx::Transform&,
                                const gfx::Point3F&,
                                bool* clipped);
   static gfx::QuadF ProjectQuad(const gfx::Transform& transform,
                                 const gfx::QuadF& quad,
                                 bool* clipped);
   static gfx::PointF ProjectPoint(const gfx::Transform& transform,
                                   const gfx::PointF& point,
                                   bool* clipped);
+  // Identical to the above function, but coerces the homogeneous coordinate to
+  // a 3d rather than a 2d point.
+  static gfx::Point3F ProjectPoint3D(const gfx::Transform& transform,
+                                     const gfx::PointF& point,
+                                     bool* clipped);
 
   static gfx::Vector2dF ComputeTransform2dScaleComponents(const gfx::Transform&,
                                                           float fallbackValue);
 
   // Makes a rect that has the same relationship to input_outer_rect as
   // scale_inner_rect has to scale_outer_rect. scale_inner_rect should be
   // contained within scale_outer_rect, and likewise the rectangle that is
   // returned will be within input_outer_rect at a similar relative, scaled
   // position.
   static gfx::RectF ScaleRectProportional(const gfx::RectF& input_outer_rect,
@@ skipping 24 matching lines @@
 
   // Returns a base::Value representation of the floating point value.
   // If the value is inf, returns max double/float representation.
   static scoped_ptr<base::Value> AsValueSafely(double value);
   static scoped_ptr<base::Value> AsValueSafely(float value);
 };
 
 }  // namespace cc
 
 #endif  // CC_BASE_MATH_UTIL_H_