Add the old Bullet 2.x obsolete demos, and CMake buildsystem files, and gradually move them to newer Bullet 3.x structure

Use statically linked freeglut, instead of dynamic glut for the obsolete Bullet 2.x demos
Add the 'reset' method to b3GpuDynamicsWorld, and use it in the BasicGpuDemo (pretty slow in debug mode, use release mode)
Don't crash in btCollisionWorld, if there is no collision dispatcher

ObsoleteDemos/NativeClient/opengl_context.cc

@@ -0,0 +1,72 @@
+// Copyright (c) 2011 The Native Client 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 "opengl_context.h"
+
+#include <pthread.h>
+#include "ppapi/gles2/gl2ext_ppapi.h"
+
+namespace {
+// This is called by the brower when the 3D context has been flushed to the
+// browser window.
+void FlushCallback(void* data, int32_t result) {
+  static_cast<tumbler::OpenGLContext*>(data)->set_flush_pending(false);
+}
+}  // namespace
+
+namespace tumbler {
+
+OpenGLContext::OpenGLContext(pp::Instance* instance)
+    : pp::Graphics3DClient_Dev(instance),
+      flush_pending_(false) {
+  pp::Module* module = pp::Module::Get();
+  assert(module);
+  gles2_interface_ = static_cast<const struct PPB_OpenGLES2_Dev*>(
+      module->GetBrowserInterface(PPB_OPENGLES2_DEV_INTERFACE));
+  assert(gles2_interface_);
+}
+
+OpenGLContext::~OpenGLContext() {
+  glSetCurrentContextPPAPI(0);
+}
+
+bool OpenGLContext::MakeContextCurrent(pp::Instance* instance) {
+  if (instance == NULL) {
+    glSetCurrentContextPPAPI(0);
+    return false;
+  }
+  // Lazily create the Pepper context.
+  if (context_.is_null()) {
+    context_ = pp::Context3D_Dev(*instance, 0, pp::Context3D_Dev(), NULL);
+    if (context_.is_null()) {
+      glSetCurrentContextPPAPI(0);
+      return false;
+    }
+    surface_ = pp::Surface3D_Dev(*instance, 0, NULL);
+    context_.BindSurfaces(surface_, surface_);
+    instance->BindGraphics(surface_);
+  }
+  glSetCurrentContextPPAPI(context_.pp_resource());
+  return true;
+}
+
+void OpenGLContext::InvalidateContext(pp::Instance* instance) {
+  if (instance == NULL)
+    return;
+  // Unbind the existing surface and re-bind to null surfaces.
+  instance->BindGraphics(pp::Surface3D_Dev());
+  context_.BindSurfaces(pp::Surface3D_Dev(), pp::Surface3D_Dev());
+  glSetCurrentContextPPAPI(0);
+}
+
+void OpenGLContext::FlushContext() {
+  if (flush_pending()) {
+    // A flush is pending so do nothing; just drop this flush on the floor.
+    return;
+  }
+  set_flush_pending(true);
+  surface_.SwapBuffers(pp::CompletionCallback(&FlushCallback, this));
+}
+}  // namespace tumbler
+