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>

6 files changed, 174 insertions, 1 deletions

diff --git a/src/core/config/embedded_linux.gypi b/src/core/config/embedded_linux.gypi
new file mode 100644
index 000000000..f192243ce
--- /dev/null
+++ b/src/core/config/embedded_linux.gypi
@@ -0,0 +1,9 @@
+{
+  'target_defaults': {
+    # patterns used to exclude chromium files from the build when we have a drop-in replacement
+    'sources/': [
+      # We are using gl_context_qt.cc instead.
+      ['exclude', 'gl_context_ozone.cc$'],
+    ],
+  },
+}
diff --git a/src/core/config/embedded_linux.pri b/src/core/config/embedded_linux.pri
index d90072ef3..8aaff3e93 100644
--- a/src/core/config/embedded_linux.pri
+++ b/src/core/config/embedded_linux.pri
@@ -1,4 +1,4 @@
-GYP_ARGS += "-D qt_os=\"embedded_linux\""
+GYP_ARGS += "-D qt_os=\"embedded_linux\" -I config/embedded_linux.gypi"
 
 GYP_CONFIG += \
     embedded=1 \
diff --git a/src/core/core_gyp_generator.pro b/src/core/core_gyp_generator.pro
index f6b513a21..4012f198a 100644
--- a/src/core/core_gyp_generator.pro
+++ b/src/core/core_gyp_generator.pro
@@ -39,6 +39,7 @@ SOURCES = \
         delegated_frame_node.cpp \
         dev_tools_http_handler_delegate_qt.cpp \
         download_manager_delegate_qt.cpp \
+        gl_context_qt.cpp \
         javascript_dialog_controller.cpp \
         javascript_dialog_manager_qt.cpp \
         process_main.cpp \
@@ -77,6 +78,7 @@ HEADERS = \
         dev_tools_http_handler_delegate_qt.h \
         download_manager_delegate_qt.h \
         chromium_gpu_helper.h \
+        gl_context_qt.h \
         javascript_dialog_controller_p.h \
         javascript_dialog_controller.h \
         javascript_dialog_manager_qt.h \
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
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** 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)
+
+
diff --git a/src/core/gl_context_qt.h b/src/core/gl_context_qt.h
new file mode 100644
index 000000000..efe8958be
--- /dev/null
+++ b/src/core/gl_context_qt.h
@@ -0,0 +1,69 @@
+/****************************************************************************
+**
+** 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
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** 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.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef GL_GL_CONTEXT_QT_H_
+#define GL_GL_CONTEXT_QT_H_
+
+#include <QObject>
+
+QT_BEGIN_NAMESPACE
+
+namespace gfx {
+class GLContext;
+class GLSurface;
+}
+
+class GLContextHelper : public QObject {
+    Q_OBJECT
+public:
+    static void initialize();
+    static bool initializeContext(gfx::GLContext* context, gfx::GLSurface* surface);
+
+private:
+    Q_INVOKABLE bool initializeContextOnBrowserThread(gfx::GLContext* context, gfx::GLSurface* surface);
+
+    static GLContextHelper* contextHelper;
+};
+
+QT_END_NAMESPACE
+
+#endif
+
diff --git a/src/core/web_engine_context.cpp b/src/core/web_engine_context.cpp
index 7fd7e577d..b4e54aae1 100644
--- a/src/core/web_engine_context.cpp
+++ b/src/core/web_engine_context.cpp
@@ -68,6 +68,7 @@
 #include "content_browser_client_qt.h"
 #include "content_client_qt.h"
 #include "content_main_delegate_qt.h"
+#include "gl_context_qt.h"
 #include "type_conversion.h"
 #include "web_engine_library_info.h"
 #include <QGuiApplication>
@@ -152,6 +153,8 @@ WebEngineContext::WebEngineContext()
     parsedCommandLine->AppendSwitch(cc::switches::kDisable4444Textures);
 #endif
 
+    GLContextHelper::initialize();
+
     // Tell Chromium to use EGL instead of GLX if the Qt xcb plugin also does.
     if (qApp->platformName() == QStringLiteral("xcb") && qApp->platformNativeInterface()->nativeResourceForWindow(QByteArrayLiteral("egldisplay"), 0))
         parsedCommandLine->AppendSwitchASCII(switches::kUseGL, gfx::kGLImplementationEGLName);