Add GLContextHelper class for EGL context creation.

Shared EGL contexts should always be created on the same
thread, as otherwise context creation might fail.
We use a GLContextHelper singleton that is initialized
on startup and creates the contexts when requested
through a BlockingQueuedConnection.

There is a pretty and a correct solution for this problem.
This is the pretty one. It is based on the assumption
that Chromium decides to use the same or a similar enough
configuration for the EGLContext as Qt previously did.
But we prefer pretty over correct as the correct solution
would potentially impose a layering violation.

This is enabled for all embedded linux devices.

Change-Id: I910cc90d0f87fd6d1fe0a475b17ba56cd8c503f6
Reviewed-by: Jocelyn Turcotte <jocelyn.turcotte@digia.com>

1 files changed, 90 insertions, 0 deletions

diff --git a/src/core/gl_context_qt.cpp b/src/core/gl_context_qt.cpp
new file mode 100644
index 000000000..1d51292dc
--- /dev/null
+++ b/src/core/gl_context_qt.cpp
@@ -0,0 +1,90 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the QtWebEngine module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
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+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "gl_context_qt.h"
+
+#include "ui/gl/gl_context_egl.h"
+
+QT_BEGIN_NAMESPACE
+
+GLContextHelper* GLContextHelper::contextHelper = 0;
+
+void GLContextHelper::initialize()
+{
+    if (!contextHelper)
+        contextHelper = new GLContextHelper;
+}
+
+bool GLContextHelper::initializeContextOnBrowserThread(gfx::GLContext* context, gfx::GLSurface* surface)
+{
+    return context->Initialize(surface, gfx::PreferDiscreteGpu);
+}
+
+bool GLContextHelper::initializeContext(gfx::GLContext* context, gfx::GLSurface* surface)
+{
+    bool ret = false;
+    QMetaObject::invokeMethod(contextHelper, "initializeContextOnBrowserThread", Qt::BlockingQueuedConnection,
+            Q_RETURN_ARG(bool, ret),
+            Q_ARG(gfx::GLContext*, context),
+            Q_ARG(gfx::GLSurface*, surface));
+    return ret;
+}
+
+QT_END_NAMESPACE
+
+#if defined(USE_OZONE)
+
+namespace gfx {
+
+scoped_refptr<GLContext> GLContext::CreateGLContext(GLShareGroup* share_group, GLSurface* compatible_surface, GpuPreference gpu_preference)
+{
+    scoped_refptr<GLContext> context(new GLContextEGL(share_group));
+    if (!GLContextHelper::initializeContext(context.get(), compatible_surface))
+        return NULL;
+
+    return context;
+}
+
+}  // namespace gfx
+
+#endif // defined(USE_OZONE)
+
+