Add Vector2d classes that represent offsets, instead of using Point.

Previously Point served two purposes, to be a position in 2d space, and also
an offset from the origin. This introduces a Vector2d class to represent an
offset, allowing typesafety checks for geometric operations.

The following are now the case:

Point +/- Vector = Point
- A point plus/minus an offset gives you a point at a position offset by the
vector.

Vector +/- Vector = Vector
- Two offsets can be added together to make a new offset.

Point - Point = Vector
- Subtracting one point from another gives you the offset between the two
points.

We add some new methods to perform these operations:

Rect::OffsetFromOrigin() gives the offset between the position of the rect
and the origin.

Point::OffsetFromOrigin() gives the offset between the point and the origin.

PointAtOffsetFromOrigin(Vector2d) converts a Vector2d to a Point at the given
offset away from the origin.

Rect::Offset(), Point::Add(), and Point::Subtract() now receive a Vector2d
instead of a point.

BUG=147395
R=sky

Review URL: https://codereview.chromium.org/11269022

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@165198 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 2 insertions, 1 deletions

diff --git a/WATCHLISTS b/WATCHLISTS
index 12a0332..f98517b 100644
--- a/WATCHLISTS
+++ b/WATCHLISTS
@@ -199,7 +199,8 @@
       'filepath': 'ui/gfx/rect|'\
                   'ui/gfx/point|'\
                   'ui/gfx/size|'\
-                  'ui/gfx/transform',
+                  'ui/gfx/transform|'\
+                  'ui/gfx/vector2d',
     },
     'gpu': {
       'filepath': 'gpu/',