Fix up some types in the API.

ppapi/cpp/core.h

Index: ppapi/cpp/core.h
diff --git a/ppapi/cpp/core.h b/ppapi/cpp/core.h
index 50c89d5af0d4ad3092638be27d859517599e5dfd..138c83203a7048051ccce8a892b8f7cb91e5c314 100644
--- a/ppapi/cpp/core.h
+++ b/ppapi/cpp/core.h
@@ -27,10 +27,10 @@ class Core {
     interface_->ReleaseResource(resource);
   }
 
-  void* MemAlloc(size_t num_bytes) {
+  void* MemAlloc(uint32_t num_bytes) {
     return interface_->MemAlloc(num_bytes);
   }
-  void MemFree(void* ptr) {
+  void MemFree(const void* ptr) {
     interface_->MemFree(ptr);
   }