Merge remote-tracking branch 'origin/5.7' into 5.8

Conflicts:
	src/core/content_browser_client_qt.cpp
	src/core/content_browser_client_qt.h
	src/core/gl_surface_qt.cpp
	src/core/print_view_manager_qt.cpp
	src/core/web_contents_delegate_qt.cpp
	src/core/web_engine_context.cpp
	src/webengine/doc/src/qtwebengine-overview.qdoc
	src/webengine/doc/src/qtwebengine-platform-notes.qdoc
	src/webenginewidgets/render_widget_host_view_qt_delegate_widget.cpp
	src/webenginewidgets/webenginewidgets.pro
	sync.profile

Change-Id: I44495f4d899580c882d6b86d68d7f6b77c8e91f6

1 files changed, 32 insertions, 23 deletions

diff --git a/src/core/gl_surface_qt.cpp b/src/core/gl_surface_qt.cpp
index e88a26715..74bb32d1f 100644
--- a/src/core/gl_surface_qt.cpp
+++ b/src/core/gl_surface_qt.cpp
@@ -90,6 +90,9 @@ void* g_display;
 const char* g_extensions = NULL;
 
 bool g_egl_surfaceless_context_supported = false;
+
+bool g_initializedEGL = false;
+
 }  // namespace
 
 
@@ -573,11 +576,17 @@ bool InitializeGLOneOffPlatform()
         return GLSurfaceQtEGL::InitializeOneOff();
 
     if (GetGLImplementation() == kGLImplementationDesktopGL) {
-#if defined(USE_X11)
-        return GLSurfaceQtGLX::InitializeOneOff();
-#elif defined(OS_WIN)
+#if defined(OS_WIN)
         return GLSurfaceQtWGL::InitializeOneOff();
+#elif defined(USE_X11)
+        if (GLSurfaceQtGLX::InitializeOneOff())
+            return true;
 #endif
+        // Fallback to trying EGL with desktop GL.
+        if (GLSurfaceQtEGL::InitializeOneOff()) {
+            g_initializedEGL = true;
+            return true;
+        }
     }
 
     return false;
@@ -586,40 +595,40 @@ bool InitializeGLOneOffPlatform()
 scoped_refptr<GLSurface>
 CreateOffscreenGLSurface(const gfx::Size& size)
 {
+    scoped_refptr<GLSurface> surface;
     switch (GetGLImplementation()) {
     case kGLImplementationDesktopGLCoreProfile:
     case kGLImplementationDesktopGL: {
-#if defined(USE_X11)
-        scoped_refptr<GLSurface> surface = new GLSurfaceQtGLX(size);
-        if (!surface->Initialize())
-            return NULL;
-        return surface;
-#elif defined(OS_WIN)
-        scoped_refptr<GLSurface> surface = new GLSurfaceQtWGL(size);
-        if (!surface->Initialize())
-            return NULL;
-        return surface;
-#else
-        LOG(ERROR) << "Desktop GL is not supported on this platform.";
-        Q_UNREACHABLE();
-        return NULL;
+#if defined(OS_WIN)
+        surface = new GLSurfaceQtWGL(size);
+        if (surface->Initialize())
+            return surface;
+        break;
+#elif defined(USE_X11)
+        if (!g_initializedEGL) {
+            surface = new GLSurfaceQtGLX(size);
+            if (surface->Initialize())
+                return surface;
+        }
+        // no break
 #endif
     }
     case kGLImplementationEGLGLES2: {
-        scoped_refptr<GLSurface> surface;
         if (g_egl_surfaceless_context_supported)
             surface = new GLSurfacelessQtEGL(size);
         else
             surface = new GLSurfaceQtEGL(size);
 
-        if (!surface->Initialize())
-            return NULL;
-        return surface;
+        if (surface->Initialize())
+            return surface;
+        break;
     }
     default:
-        Q_UNREACHABLE();
-        return NULL;
+        break;
     }
+    LOG(ERROR) << "Requested OpenGL platform is not supported.";
+    Q_UNREACHABLE();
+    return NULL;
 }
 
 scoped_refptr<GLSurface>