gl_surface_egl: ensure off and on screen surfaces use the same EGLConfig

ui/gl/gl_surface_egl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gl/gl_surface_egl.h"
 
 #if defined(OS_ANDROID)
 #include <android/native_window_jni.h>
 #endif
 
@@ skipping 17 matching lines @@
 extern "C" {
 #include <X11/Xlib.h>
 }
 #endif
 
 #if defined (USE_OZONE)
 #include "ui/ozone/public/ozone_platform.h"
 #include "ui/ozone/public/surface_factory_ozone.h"
 #endif
 
+#if defined(USE_X11) && !defined(OS_CHROMEOS)
+#include "ui/gfx/x/x11_switches.h"
+#endif
+
 #if !defined(EGL_FIXED_SIZE_ANGLE)
 #define EGL_FIXED_SIZE_ANGLE 0x3201
 #endif
 
 #if !defined(EGL_OPENGL_ES3_BIT)
 #define EGL_OPENGL_ES3_BIT 0x00000040
 #endif
 
 // From ANGLE's egl/eglext.h.
 
@@ skipping 233 matching lines @@
     EGL_RED_SIZE, 8,
     EGL_RENDERABLE_TYPE, renderable_type,
     EGL_SURFACE_TYPE, EGL_WINDOW_BIT | EGL_PBUFFER_BIT,
     EGL_NONE
   };
 
 #if defined(USE_OZONE)
   const EGLint* config_attribs = ui::OzonePlatform::GetInstance()
                                      ->GetSurfaceFactoryOzone()
                                      ->GetEGLSurfaceProperties(kConfigAttribs);
+#elif defined(USE_X11) && !defined(OS_CHROMEOS)
+  const EGLint* config_attribs = kConfigAttribs;
+
+  if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableTransparentVisuals)) {
+    const int kBufferSizeOffset = 1;
+    const int kAlphaSizeOffset = 3;
+    EGLint* config_non_const = const_cast<EGLint*>(kConfigAttribs);

[hendrikw, 2015/11/11 23:55:46]

Not a big fan of this const stuff.

How about above the declaration of kConfigAttribs you do something like:

  EGLint buffer_size = 32;
  EGLint alpha_size = 8;

#if defined(USE_X11) && !defined(OS_CHROMEOS)
  if (!base::CommandLine::ForCurrentProcess()->HasSwitch(...) {
    buffer_size = 24;
    alpha_size = 0;
  }
#endif

And then use those vars in the declaration of kConfigAttribs?

[Julien Isorce Samsung, 2015/11/12 11:06:48]

Much easier to read indeed, thx. I addressed remarks and uploaded "Patch Set 4".

+
+    config_non_const[kBufferSizeOffset] = 24;
+    config_non_const[kAlphaSizeOffset] = 0;
+
+    config_attribs = config_non_const;
+  }
 #else
   const EGLint* config_attribs = kConfigAttribs;
 #endif
 
   EGLint num_configs;
   if (!eglChooseConfig(g_display,
                        config_attribs,
                        NULL,
                        0,
                        &num_configs)) {
@@ skipping 613 matching lines @@
 }
 
 void* SurfacelessEGL::GetShareHandle() {
   return NULL;
 }
 
 SurfacelessEGL::~SurfacelessEGL() {
 }
 
 }  // namespace gfx