Change X11 error handler override to allow easy X11 error checking.

ui/gfx/gl/gl_context_glx.cc

Index: ui/gfx/gl/gl_context_glx.cc
diff --git a/ui/gfx/gl/gl_context_glx.cc b/ui/gfx/gl/gl_context_glx.cc
index a23f1a9b988063d7c7f84db3253fa23d6b3b4bc9..7f702cce60af295407ff8c125eed40e6e03fc90e 100644
--- a/ui/gfx/gl/gl_context_glx.cc
+++ b/ui/gfx/gl/gl_context_glx.cc
@@ -11,10 +11,16 @@ extern "C" {
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "third_party/mesa/MesaLib/include/GL/osmesa.h"
+#include "ui/base/x/x11_util.h"
+#include "ui/base/x/x11_util_internal.h"
 #include "ui/gfx/gl/gl_bindings.h"
 #include "ui/gfx/gl/gl_implementation.h"
 #include "ui/gfx/gl/gl_surface_glx.h"
 
+#define CHECK_X_ERROR() do { \
+    CHECK(!ui::GetLastX11Error(gfx::GLSurfaceGLX::GetDisplay())); \
+  } while(0)
+
 namespace gfx {
 
 namespace {
@@ -88,6 +94,8 @@ bool GLContextGLX::Initialize(GLSurface* compatible_surface) {
     }
   }
 
+  CHECK_X_ERROR();
+
   if (!context_) {
     // The means by which the context is created depends on whether
     // the drawable type works reliably with GLX 1.3. If it does not
@@ -113,6 +121,8 @@ bool GLContextGLX::Initialize(GLSurface* compatible_surface) {
         return false;
       }
 
+      CHECK_X_ERROR();
+
       XVisualInfo visual_info_template;
       visual_info_template.visualid = XVisualIDFromVisual(attributes.visual);
 
@@ -136,6 +146,7 @@ bool GLContextGLX::Initialize(GLSurface* compatible_surface) {
           True);
     }
   }
+  CHECK_X_ERROR();
 
   if (!context_) {
     LOG(ERROR) << "Couldn't create GL context.";