GLSurface::Resize implementations release the current context if they are current before resize.

ui/gfx/gl/gl_surface_osmesa.cc

 // Copyright (c) 2011 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/gfx/gl/gl_surface_osmesa.h"
 #include "base/logging.h"
 #include "ui/gfx/gl/gl_bindings.h"
+#include "ui/gfx/gl/gl_context.h"
 
 namespace gfx {
 
 GLSurfaceOSMesa::GLSurfaceOSMesa(unsigned format, const gfx::Size& size)
     : format_(format),
       size_(size) {
 }
 
 GLSurfaceOSMesa::~GLSurfaceOSMesa() {
   Destroy();
 }
 
 bool GLSurfaceOSMesa::Resize(const gfx::Size& new_size) {
   if (new_size == size_)
     return true;
 
+  GLContext* current_context = GLContext::GetCurrent();
+  bool was_current = current_context && current_context->IsCurrent(this);
+  if (was_current)
+    current_context->ReleaseCurrent(this);
+
   // Preserve the old buffer.
   scoped_array<int32> old_buffer(buffer_.release());
 
   // Allocate a new one.
   AllocateBuffer(new_size);
 
   // Copy the old back buffer into the new buffer.
   int copy_width = std::min(size_.width(), new_size.width());
   int copy_height = std::min(size_.height(), new_size.height());
   for (int y = 0; y < copy_height; ++y) {
     for (int x = 0; x < copy_width; ++x) {
       buffer_[y * new_size.width() + x] = old_buffer[y * size_.width() + x];
     }
   }
 
   size_ = new_size;
+
+  if (was_current)
+    return current_context->MakeCurrent(this);
+
   return true;
 }
 
 bool GLSurfaceOSMesa::Initialize() {
   AllocateBuffer(size_);
   return true;
 }
 
 void GLSurfaceOSMesa::Destroy() {
   buffer_.reset();
@@ skipping 19 matching lines @@
 unsigned GLSurfaceOSMesa::GetFormat() {
   return format_;
 }
 
 void GLSurfaceOSMesa::AllocateBuffer(const Size& size) {
   buffer_.reset(new int32[size.GetArea()]);
   memset(buffer_.get(), 0, size.GetArea() * sizeof(buffer_[0]));
 }
 
 }  // namespace gfx