Rename cc::ResourceProvider::ResourceId to cc::ResourceId and move it to its own file.

cc/resources/returned_resource.h

Index: cc/resources/returned_resource.h
diff --git a/cc/resources/returned_resource.h b/cc/resources/returned_resource.h
index e2008b415a3c7865d46896a69daddc1b89c2f833..1244923fc13c69e8bec3693734c238d08e4fab1d 100644
--- a/cc/resources/returned_resource.h
+++ b/cc/resources/returned_resource.h
@@ -9,12 +9,13 @@
 
 #include "base/basictypes.h"
 #include "cc/base/cc_export.h"
+#include "cc/resources/resource_id.h"
 
 namespace cc {
 
 struct CC_EXPORT ReturnedResource {
   ReturnedResource() : id(0), sync_point(0), count(0), lost(false) {}
-  unsigned id;
+  ResourceId id;
   unsigned sync_point;
   int count;
   bool lost;