evas_clip: do not set clip->changed to true

evas_clip: do not set clip->changed to true

Summary:
[Issuse]
The issue solved by this commit occurs with 'export EVAS_GL_PARTIAL_DISABLE=0'.

The _efl_canvas_object_clip_set set clip->changed to true, but did not add the
clip object to e->pending_objects. So there is no chance to reset it to false.
(Please refer to evas_render_object_recalc.)

The clip->changed is always ture so its clipees cannot change its 'changed'
to true.  Because if 'changed' is true, evas_object_change returns before
calling evas_object_change for its clipees. (Please see evas_object_change.)
So 'changed' of clipees is false always, and clipees cannot call render_pre
in _evas_render_phase1_direct, and eglSwapBuffersWithDamage is not called.
This caused rendering issue.

This could be rare case. The _efl_canvas_object_clip_set is called when the
clipper and its clipees are out of view.

[Solution]
I would like to explain why removing line setting clip->changed to true makes
sense. First, the following commit added line setting clip->changed to true.

(1) committ 5e8d46e884930f109a28147cda4ce002e6836017
    Author: Carsten Haitzler <raster@rasterman.com>
    Date:   Wed Sep 22 04:37:51 2004 +0000

        clip bug fix :)

And following commit removed line calling evas_damage_rectangle_add which is
part of commit (1) above.

(2) commit 8767a80b0dbda4e2c3a6b2a41a04bf35f43a3ed1
    Author: Carsten Haitzler (Rasterman) <raster@rasterman.com>
    Date:   Wed Apr 16 16:14:16 2014 +0900

        fix overdraw issue in evas when clips change

Between above two commits, another commit calling evas_object_change(clip) was
added. This commit sets clip->changed to ture, and adds clip object to
e->pending_objects by evas_object_change -> evas_render_object_recalc.

(3) commit 4aca7949f581eaaf943785759b542acd8fc6794c
    Author: Carsten Haitzler <raster@rasterman.com>
    Date:   Wed Nov 2 04:03:55 2005 +0000

        fix excess overdraw bug

So we do not need the remains of commit (1). REMOVE!! :-]

Reviewers: raster, Hermet, jypark

Reviewed By: Hermet

Subscribers: cedric, #reviewers, #committers

Tags: #efl

Differential Revision: https://phab.enlightenment.org/D7767