Revert of [Sync] Add size and crc32c to AttachmentId.

sync/api/attachments/attachment_unittest.cc

Index: sync/api/attachments/attachment_unittest.cc
diff --git a/sync/api/attachments/attachment_unittest.cc b/sync/api/attachments/attachment_unittest.cc
index cd1e3e4ca7c7113f414a02ed256540139c099f7b..49b4cabf1ac847e59fa8cbd500871aa18f38fa44 100644
--- a/sync/api/attachments/attachment_unittest.cc
+++ b/sync/api/attachments/attachment_unittest.cc
@@ -38,11 +38,11 @@
 }
 
 TEST_F(AttachmentTest, CreateFromParts_HappyCase) {
+  AttachmentId id = AttachmentId::Create();
   scoped_refptr<base::RefCountedString> some_data(new base::RefCountedString);
   some_data->data() = kAttachmentData;
   uint32_t crc32c = ComputeCrc32c(some_data);
-  AttachmentId id = AttachmentId::Create(some_data->size(), crc32c);
-  Attachment a = Attachment::CreateFromParts(id, some_data);
+  Attachment a = Attachment::CreateFromParts(id, some_data, crc32c);
   EXPECT_EQ(id, a.GetId());
   EXPECT_EQ(some_data, a.GetData());
 }