Added PPB_Graphics3D_Dev::Resize to let plugins resize the backing surface.

ppapi/thunk/ppb_graphics_3d_thunk.cc

Index: ppapi/thunk/ppb_graphics_3d_thunk.cc
===================================================================
--- ppapi/thunk/ppb_graphics_3d_thunk.cc	(revision 94518)
+++ ppapi/thunk/ppb_graphics_3d_thunk.cc	(working copy)
@@ -64,6 +64,13 @@
   return enter.object()->SetAttribs(attrib_list);
 }
 
+int32_t ResizeBuffers(PP_Resource graphics_3d, int32_t width, int32_t height) {
+  EnterGraphics3D enter(graphics_3d, true);
+  if (enter.failed())
+    return PP_ERROR_BADRESOURCE;
+  return enter.object()->ResizeBuffers(width, height);
+}
+
 int32_t SwapBuffers(PP_Resource graphics_3d, PP_CompletionCallback callback) {
   EnterGraphics3D enter(graphics_3d, true);
   if (enter.failed())
@@ -80,6 +87,7 @@
   &IsGraphics3D,
   &GetAttribs,
   &SetAttribs,
+  &ResizeBuffers,
   &SwapBuffers
 };