[GTK] [EFL] Collapse duplicate WebGL support code

[GTK] [EFL] Collapse duplicate WebGL support code
https://bugs.webkit.org/show_bug.cgi?id=78970

Patch by Martin Robinson <mrobinson@igalia.com> on 2012-02-20
Reviewed by Gustavo Noronha Silva.

No new tests. This just cleans up duplicated code.

Centralize duplicated WebGL code for EFL and GTK+ in the Cairo
directory. This is in preparation for the changes necessary to
connect WebGL to the TextureMapper AC.

* GNUmakefile.list.am: Update source list.
* PlatformEfl.cmake: Update source list.
* platform/graphics/cairo/DrawingBufferCairo.cpp: Renamed from Source/WebCore/platform/graphics/gtk/DrawingBufferGtk.cpp.
* platform/graphics/cairo/GraphicsContext3DCairo.cpp: Integrated the code From GraphicsContext3DGtk.cpp.
* platform/graphics/efl/DrawingBufferEfl.cpp: Removed.
* platform/graphics/efl/GraphicsContext3DEfl.cpp: Removed.
* platform/graphics/gtk/GraphicsContext3DGtk.cpp: Removed.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@108289 268f45cc-cd09-0410-ab3c-d52691b4dbfc