Revert of [#7] Pass gfx structs by const ref (gfx::Size)  (https://codereview.chromium.org/145313006/)

Reason for revert:
Suspected of breaking the Linux ASAN tests ( http://build.chromium.org/p/chromium.memory/builders/Linux%20ASAN%20Tests%20%283%29/builds/22104 )

Original issue's description:
> [#7] Pass gfx::Size by const ref.
>
> 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 and some
> other scenarios mentioned in the bug.
>
> BUG=159273
>
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=247426

TBR=danakj@chromium.org,enne@chromium.org,bulach@chromium.org,piman@chromium.org,prashant.n@samsung.com
NOTREECHECKS=true
NOTRY=true
BUG=159273

Review URL: https://codereview.chromium.org/142863008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247437 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247437