21 struct Vector2 {  struct
22   Vector2() : x(0), y(0) {}  in Vector2()  function
23   Vector2(float x, float y) : x(x), y(y) {}  in Vector2()  argument
24   Vector2(const Vector2& other) : x(other.x), y(other.y) {}  in Vector2()  argument
25   explicit Vector2(const FingerState& state) : x(state.position_x),  in Vector2()  argument
28   Vector2 Sub(const Vector2& other) {  in Sub()  argument
29     return Vector2(x - other.x, y - other.y);  in Sub()
32   Vector2 Add(const Vector2& other) {  in Add()  argument
33     return Vector2(x + other.x, y + other.y);  in Add()
42   bool operator==(const Vector2& that) const {  argument
45   bool operator!=(const Vector2& that) const {
53 extern Vector2 Add(const Vector2& left, const Vector2& right);  argument
54 extern Vector2 Sub(const Vector2& left, const Vector2& right);
55 extern float Dot(const Vector2& left, const Vector2& right);
88   Vector2 position() const { return position_; }  in position()
91   Vector2 delta() const { return delta_; }  in delta()
94   Vector2 origin_position() const { return origin_position_; }  in origin_position()
96   Vector2 origin_delta() const { return Sub(position_, origin_position_); }  in origin_delta()
100   Vector2 start_position() const { return start_position_; }  in start_position()
102   Vector2 start_delta() const { return Sub(position_, start_position_); }  in start_delta()
111   Vector2 position_;
112   Vector2 delta_;
113   Vector2 origin_position_;
114   Vector2 start_position_;
127   bool CloseEnoughToGesture(const Vector2& pos_a,
128                             const Vector2& pos_b) const;