Android: cleanup gtest_target_type conditions.

For a long time (crrev.com/133053) OS==android implies:
gtest_target_type=shared_library
Cleanup the spurious conditions and obsolete TODOs.

BUG=

Review URL: https://codereview.chromium.org/300193002

git-svn-id: svn://svn.chromium.org/blink/trunk@174875 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make screen.orientation implementation use WebScreenInfo::orientationType

Make screen.orientation implementation use WebScreenInfo::orientationType
instead of Plaform.h's setScreenOrientationListener(). This is better because:
- We can always retrieve a valid screen orientation even before the first
  orientationchange event is fired. i.e. there is no more initialization
  problem.
- The orientation is specific to a Frame instead of being global. This supports
  environment with multiple screens.

Also stop firing the 'orientationchange' event from ScreenOrientationController
anymore and reuse the existing firing code
in LocalFrame::sendOrientationChangeEvent() instead. This avoids firing the
'orientationchange' event twice when screen orientation is enabled. It also
avoids depending on Plaform.h's setScreenOrientationListener() which is
deprecated as it is global instead of per-view (i.e. lack of multi-screen
support).

I tested that the feature is still working on Android target using the
following test app:
http://jsbin.com/IJapIVE/53

R=jochen@chromium.org, mlamouri@chromium.org
BUG=162827
TEST=screen_orientation/orientationchange-event-subframe.html

Review URL: https://codereview.chromium.org/277413002

git-svn-id: svn://svn.chromium.org/blink/trunk@174876 bbb929c8-8fbe-4397-9dbb-9b2b20218538