Enhance the PPAPI enter tracking.

ppapi/thunk/ppb_graphics_2d_thunk.cc

Index: ppapi/thunk/ppb_graphics_2d_thunk.cc
diff --git a/ppapi/thunk/ppb_graphics_2d_thunk.cc b/ppapi/thunk/ppb_graphics_2d_thunk.cc
index e42d0021027b6e182fec9454f8c161733a0efcca..edb7ea97846b22d0080ac1c4811f3035d5d21373 100644
--- a/ppapi/thunk/ppb_graphics_2d_thunk.cc
+++ b/ppapi/thunk/ppb_graphics_2d_thunk.cc
@@ -16,24 +16,26 @@ namespace thunk {
 
 namespace {
 
+typedef EnterResource<PPB_Graphics2D_API> EnterGraphics2D;
+
 PP_Resource Create(PP_Instance instance,
                    const PP_Size* size,
                    PP_Bool is_always_opaque) {
-  EnterFunction<ResourceCreationAPI> enter(instance, true);
+  EnterResourceCreation enter(instance);
   if (enter.failed())
     return 0;
   return enter.functions()->CreateGraphics2D(instance, *size, is_always_opaque);
 }
 
 PP_Bool IsGraphics2D(PP_Resource resource) {
-  EnterResource<PPB_Graphics2D_API> enter(resource, false);
+  EnterGraphics2D enter(resource, false);
   return enter.succeeded() ? PP_TRUE : PP_FALSE;
 }
 
 PP_Bool Describe(PP_Resource graphics_2d,
                  PP_Size* size,
                  PP_Bool* is_always_opaque) {
-  EnterResource<PPB_Graphics2D_API> enter(graphics_2d, true);
+  EnterGraphics2D enter(graphics_2d, true);
   if (enter.failed()) {
     size->width = 0;
     size->height = 0;
@@ -47,7 +49,7 @@ void PaintImageData(PP_Resource graphics_2d,
                     PP_Resource image_data,
                     const PP_Point* top_left,
                     const PP_Rect* src_rect) {
-  EnterResource<PPB_Graphics2D_API> enter(graphics_2d, true);
+  EnterGraphics2D enter(graphics_2d, true);
   if (enter.failed())
     return;
   enter.object()->PaintImageData(image_data, top_left, src_rect);
@@ -56,14 +58,14 @@ void PaintImageData(PP_Resource graphics_2d,
 void Scroll(PP_Resource graphics_2d,
             const PP_Rect* clip_rect,
             const PP_Point* amount) {
-  EnterResource<PPB_Graphics2D_API> enter(graphics_2d, true);
+  EnterGraphics2D enter(graphics_2d, true);
   if (enter.failed())
     return;
   enter.object()->Scroll(clip_rect, amount);
 }
 
 void ReplaceContents(PP_Resource graphics_2d, PP_Resource image_data) {
-  EnterResource<PPB_Graphics2D_API> enter(graphics_2d, true);
+  EnterGraphics2D enter(graphics_2d, true);
   if (enter.failed())
     return;
   enter.object()->ReplaceContents(image_data);
@@ -71,11 +73,10 @@ void ReplaceContents(PP_Resource graphics_2d, PP_Resource image_data) {
 
 int32_t Flush(PP_Resource graphics_2d,
               PP_CompletionCallback callback) {
-  EnterResource<PPB_Graphics2D_API> enter(graphics_2d, true);
+  EnterGraphics2D enter(graphics_2d, callback, true);
   if (enter.failed())
-    return MayForceCallback(callback, PP_ERROR_BADRESOURCE);
-  int32_t result = enter.object()->Flush(callback);
-  return MayForceCallback(callback, result);
+    return enter.retval();
+  return enter.SetResult(enter.object()->Flush(callback));
 }
 
 const PPB_Graphics2D g_ppb_graphics_2d_thunk = {