Avoid letterboxing when connecting to multi-monitor hosts in full-screen.
Avoid letterboxing when connecting to multi-monitor hosts in full-screen.

Scaling a multi-monitor desktop to fit a single-monitor client ("scale-to-fit")
results in the desktop being letter-boxed, leaving much of the client area
unused.  In this case the client now prefers to scale to fit the smaller host
dimension, and have the user pan to see other parts of the host desktop
("scale-and-pan").

Scale-and-pan is used only in full-screen mode, when the client dimensions match
those of a client device monitor, and bump-scrolling can be used to pan around.

Scale-and-pan will be used when less than 65% of the client area would be
occupied by the desktop if we were to scale-to-fit.  For example:

  C: 1280x800  H: 1280x1024             -> scale-to-fit
  C: 1280x800  H: (2x1280)x1024         -> scale-and-pan (horizontal)
  C: 1280x1024 H: 1600x1200             -> scale-to-fit
  C: 1600x1200 H: 1280x(2x1024)         -> scale-and-pan (vertical)

BUG=145709


Review URL: https://chromiumcodereview.appspot.com/11369023

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@165515 0039d316-1c4b-4281-b951-d872f2087c98

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