Unify geometry test printers in a test support target.

Unify geometry test printers in a test support target.

This adds a new target which provides test support for Source/platform/.
These can be used in platform unit tests, or unit tests of targets which
depend on platform.

GYP: blink_platform_test_support (static_library)
GN: //third_party/WebKit/Source/platform:test_support (source_set)

Existing GTest print support for Source/platform/geometry/ types has been
made more consistent, and moved into this target. Both
blink_platform_unittests and webkit_unit_tests depend on it.

To avoid ODR violations, the declarations of these are in the headers
of the types that are being printed. If these are called outside unit tests,
a link error will occur.

This is similar to how ui/gfx/ does things in Chromium; it's seems like
a more reasonable approach than what we do today.

BUG=522198
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=200933

[jbroman, 2015-08-19 15:02:49]

jbroman@chromium.org changed reviewers:
+ pdr@chromium.org

[jbroman, 2015-08-19 15:02:50]

Not urgent, but I was getting annoyed with geometry types being described as
"32-byte object 00-32-00-01-...". Hopefully this is one step toward
rationalizing.

[pdr., 2015-08-20 07:11:49]

LGTM

[jbroman, 2015-08-20 15:15:24]

The CQ bit was checked by jbroman@chromium.org

[commit-bot: I haz the power, 2015-08-20 15:15:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1285413007/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1285413007/20001

[commit-bot: I haz the power, 2015-08-20 20:30:43]

Committed patchset #2 (id:20001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=200933