Pass gfx::Rect and gfx::RectF by const ref.
Avoid unneccessary copy of structures gfx::Rect & gfx::RectF
by passing them by const ref rather than value.
Any struct of size > 4 bytes should be passed by const ref.
Passing by ref for these structs is faster than passing
by value, especially when invoking function has multiple parameters.
Pass by value creates unneccessary overhead which should be avoided.
BUG=159273
Review URL: https://codereview.chromium.org/
93663004
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244224 0039d316-1c4b-4281-b951-d872f2087c98