Fix for mac/linux unit_test

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@25772 0039d316-1c4b-4281-b951-d872f2087c98

o3d/core/cross/renderer.cc

@@ -263,6 +263,8 @@ bool Renderer::StartRendering() {
     draw_elements_rendered_ = 0;
     primitives_rendered_ = 0;
     back_buffer_cleared_ = 0;
+    current_render_surface_ = NULL;
+    current_depth_surface_ = NULL;
     current_render_surface_is_back_buffer_ = true;
 
     result = PlatformSpecificStartRendering();