GPU: Keep track of the last real context and real surface made current.

ui/gl/gl_surface_osmesa.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 "base/logging.h"
 #include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_context.h"
 #include "ui/gl/gl_surface_osmesa.h"
+#include "ui/gl/scoped_make_current.h"
 
 namespace gfx {
 
 GLSurfaceOSMesa::GLSurfaceOSMesa(unsigned format, const gfx::Size& size)
     : format_(format),
       size_(size) {
 }
 
 bool GLSurfaceOSMesa::Initialize() {
   return Resize(size_);
 }
 
 void GLSurfaceOSMesa::Destroy() {
   buffer_.reset();
 }
 
 bool GLSurfaceOSMesa::Resize(const gfx::Size& new_size) {
+  scoped_ptr<ui::ScopedMakeCurrent> scoped_make_current;
   GLContext* current_context = GLContext::GetCurrent();
-  bool was_current = current_context && current_context->IsCurrent(this);
-  if (was_current)
+  bool was_current =
+      current_context && current_context->IsCurrent(this);
+  if (was_current) {
+    scoped_make_current.reset(
+        new ui::ScopedMakeCurrent(current_context, this));
     current_context->ReleaseCurrent(this);
+  }
 
   // Preserve the old buffer.
   scoped_ptr<int32[]> old_buffer(buffer_.release());
 
   // Allocate a new one.
   buffer_.reset(new int32[new_size.GetArea()]);
   memset(buffer_.get(), 0, new_size.GetArea() * sizeof(buffer_[0]));
 
   // Copy the old back buffer into the new buffer.
   if (old_buffer.get()) {
     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::IsOffscreen() {
   return true;
 }
 
 bool GLSurfaceOSMesa::SwapBuffers() {
   NOTREACHED() << "Should not call SwapBuffers on an GLSurfaceOSMesa.";
   return false;
 }
 
 gfx::Size GLSurfaceOSMesa::GetSize() {
   return size_;
 }
 
 void* GLSurfaceOSMesa::GetHandle() {
   return buffer_.get();
 }
 
 unsigned GLSurfaceOSMesa::GetFormat() {
   return format_;
 }
 
 GLSurfaceOSMesa::~GLSurfaceOSMesa() {
   Destroy();
 }
 
 }  // namespace gfx