osx: let qcombobox specify target rect when showing popup

Let qcombobox use the new API for showing a native
popup menu (introduced with 1a47595).

Change-Id: Id08ef9e59fdd47b2c1df84fa72e3a2c69fe187b0
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
qplatformmenu: remove unused and deprecated function

Now that all platforms use the popup function that
takes a target rect, lets remove the deprecated one.

This is sort of important, since QtQuick controls now
uses the new version. So if a (new) platform ends up only
implementing the old version, that can end up not
working correctly.

Change-Id: I34814b3de5ea4954cf21b161e8a834e39e5534c8
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Make QStringRef::right() consistent with QString::right()

The implementation was inconsistent with QString::right(),
and did not return the N rightmost characters but actually did
the same as QString::mid(N) (returning the rightmost size - N
characters.)

Since this function is fairly recent (Qt 5.2), is documented to
behave the same as QString::right(), and since these APIs are
meant to be interchangeable, this needs to be fixed, even though
it changes behavior.

[ChangeLog][Important Behavior Changes] Changed QStringRef::right()
to be consistent with QString::right(). The function now returns
the N right-most characters, like the documentation already claimed.

Change-Id: I2d1cd6d958dfa9354aa09f16bd27b1ed209c2d11
Task-number: QTBUG-41858
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@digia.com>
Fix QOpenGLWidget on Cocoa when used as viewport

Having a QOpenGLWidget as a graphics view viewport was not functioning
on OS X: it was showing incomplete content due to accessing the texture
attached to the framebuffer object before the rendering is complete.

On the normal path, when rendering is done via paintGL(), the flush was
there. When used as a viewport however, this path is not used. The missing
flush is now added for the other case too. For performance reasons, we will
not flush on every paint engine end(). Instead, the flush is deferred until
composition starts.

QGLWidget also featured a weird on-by-default autoFillBackground concept. To
maintain compatibility with apps that used QGLWidget as the viewport for
QGraphicsView, we will now do the same for QOpenGLWidget, but only when it
is used as a viewport. For regular QOpenGLWidgets autoFillBackground defaults
to false, like for any other widget. The docs are extended with a small section
about differences between QGLWidget and QOpenGLWidget.

Task-number: QTBUG-41046
Change-Id: I42c2033fdd2ef5815783fd640fe11373761061e0
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>
Cocoa: Send obscure events on OcclusionStateHidden

This disables animations for windows that are
completely obscured by other windows.

On examples/quick/animation, obscured CPU usage goes
from 10% to 1%.

Change-Id: I9945431e6387e406e2064c08d5aa01d5d96ef602
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@theqtcompany.com>