Update from https://crrev.com/320343

cc/resources/layer_quad.h

 // Copyright 2011 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_RESOURCES_LAYER_QUAD_H_
 #define CC_RESOURCES_LAYER_QUAD_H_
 
 #include "base/basictypes.h"
 #include "cc/base/cc_export.h"
 #include "ui/gfx/geometry/point_f.h"
 
 namespace gfx {
 class QuadF;
 }
 
 static const float kAntiAliasingInflateDistance = 0.5f;
 
 namespace cc {
 
 class CC_EXPORT LayerQuad {
  public:
   class Edge {
    public:
-    Edge() : x_(0), y_(0), z_(0) {}
+    Edge() : x_(0), y_(0), z_(0), degenerate_(false) {}
     Edge(const gfx::PointF& p, const gfx::PointF& q);
 
     float x() const { return x_; }
     float y() const { return y_; }
     float z() const { return z_; }
 
     void set_x(float x) { x_ = x; }
     void set_y(float y) { y_ = y; }
     void set_z(float z) { z_ = z; }
     void set(float x, float y, float z) {
@@ skipping 14 matching lines @@
     void scale_x(float sx) { x_ *= sx; }
     void scale_y(float sy) { y_ *= sy; }
     void scale_z(float sz) { z_ *= sz; }
     void scale(float sx, float sy, float sz) {
       x_ *= sx;
       y_ *= sy;
       z_ *= sz;
     }
     void scale(float s) { scale(s, s, s); }
 
+    bool degenerate() const { return degenerate_; }
+
     gfx::PointF Intersect(const Edge& e) const {
       return gfx::PointF(
           (y() * e.z() - e.y() * z()) / (x() * e.y() - e.x() * y()),
           (x() * e.z() - e.x() * z()) / (e.x() * y() - x() * e.y()));
     }
 
    private:
     float x_;
     float y_;
     float z_;
+    bool degenerate_;
   };
 
   LayerQuad(const Edge& left,
             const Edge& top,
             const Edge& right,
             const Edge& bottom);
   explicit LayerQuad(const gfx::QuadF& quad);
 
   Edge left() const { return left_; }
   Edge top() const { return top_; }
@@ skipping 25 matching lines @@
   Edge top_;
   Edge right_;
   Edge bottom_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerQuad);
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_LAYER_QUAD_H_