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

2 files changed, 2 insertions, 4 deletions

diff --git a/ui/app_list/page_switcher.cc b/ui/app_list/page_switcher.cc
index ba98671..1517d39 100644
--- a/ui/app_list/page_switcher.cc
+++ b/ui/app_list/page_switcher.cc
@@ -189,8 +189,7 @@ void PageSwitcher::Layout() {
                            rect.y(),
                            buttons_size.width(),
                            rect.height());
-  rect.Intersect(buttons_bounds);
-  buttons_->SetBoundsRect(rect);
+  buttons_->SetBoundsRect(gfx::IntersectRects(rect, buttons_bounds));
 }
 
 void PageSwitcher::CalculateButtonWidthAndSpacing(int contents_width) {
diff --git a/ui/app_list/search_result_view.cc b/ui/app_list/search_result_view.cc
index 7e4559d..eb6547d 100644
--- a/ui/app_list/search_result_view.cc
+++ b/ui/app_list/search_result_view.cc
@@ -200,8 +200,7 @@ void SearchResultView::OnPaint(gfx::Canvas* canvas) {
     canvas->FillRect(content_rect, kHoverAndPushedColor);
   }
 
-  gfx::Rect border_bottom(rect);
-  border_bottom.Subtract(content_rect);
+  gfx::Rect border_bottom = gfx::SubtractRects(rect, content_rect);
   canvas->FillRect(border_bottom,
                    selected ? kSelectedBorderColor : kBorderColor);