Add non-member non-mutating methods for common gfx::Rect operations.

This adds non-member methods that return a new Rect (or RectF) object
as their result instead of mutating an existing rect. We add:

Rect gfx::IntersectRects(Rect, Rect)
RectF gfx::IntersectRects(RectF, RectF)
Rect gfx::UnionRects(Rect, Rect)
RectF gfx::UnionRects(RectF, RectF)
Rect gfx::SubtractRects(Rect, Rect)
RectF gfx::SubtractRects(RectF, RectF)
RectF gfx::ScaleRect(RectF, scale)
RectF gfx::ScaleRect(RectF, x_scale, y_scale)

In CL https://codereview.chromium.org/11110004/ we made all
member methods of Rect (and RectF) mutate the existing
object, so these methods are added for cases where we want
the result to create a new object instead.

BUG=147395
R=sky

Review URL: https://codereview.chromium.org/11270042

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@164760 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 1 insertions, 2 deletions

diff --git a/ash/display/multi_display_manager.cc b/ash/display/multi_display_manager.cc
index d93321b..5911ae9 100644
--- a/ash/display/multi_display_manager.cc
+++ b/ash/display/multi_display_manager.cc
@@ -360,8 +360,7 @@ const gfx::Display& MultiDisplayManager::GetDisplayMatching(
   for (std::vector<gfx::Display>::const_iterator iter = displays_.begin();
        iter != displays_.end(); ++iter) {
     const gfx::Display& display = *iter;
-    gfx::Rect intersect = display.bounds();
-    intersect.Intersect(rect);
+    gfx::Rect intersect = gfx::IntersectRects(display.bounds(), rect);
     int area = intersect.width() * intersect.height();
     if (area > max) {
       max = area;