Fix GPU compositing (and WebGL) to work with ANGLE on Windows

Given the changes that implement GPU compositing on the UI thread (and
thus only a single thread accesses all OpenGL contexts) it is now
possible to enable GPU compositing to work together with ANGLE, which
did not work before due to ANGLE being thread-unsafe.

This requires a couple of things:
- Enable GPU compositing via kInProcessGPU switch when using ANGLE
- A small fix in GLContextHelper::getEGLDisplay() to return a
  correct "egldisplay "handle
- Improved logic when to pass the kDisableES3GLContext switch
  depending on which OpenGL ES version is requested (2 or 3)
- Adjustments in RenderWidgetHostViewQtDelegateWidget() to set up a
  correct surface format which matches the shared
  context OpenGL ES major version
- A recent enough version of ANGLE (due to bugs calling
  glTexImage2D with an unsupported internal texture format for
  GL_DEPTH_COMPONENT, from inside
  gpu::gles2::IsWebGLDrawBuffersSupported)

By default if no special QSurfaceFormat is set as the default
surface format, using ANGLE will create an OpenGL ES 2 context,
and will thus provide support only for WebGL 1.

To enable OpenGL ES 3 / WebGL 2 support, make sure to set a
default QSurfaceFormat with major version set to 3, and enable
ANGLE either via QT_OPENGL=angle or
QGuiApplication::setAttribute(Qt::AA_UseOpenGLES).

The default surface format must be set before the Q*App instance
is created.

Manual test "webgl" added.

Task-number: QTBUG-53908
Task-number: QTBUG-55604
Task-number: QTBUG-69236
Change-Id: Ic31dfdff1ca22d4689db5cf64126d7d12790aa76
Reviewed-by: Jüri Valdmann <juri.valdmann@qt.io>
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

0 files changed, 0 insertions, 0 deletions