[Sync] Add size and crc32c to AttachmentId.

sync/api/attachments/attachment_metadata_unittest.cc

Index: sync/api/attachments/attachment_metadata_unittest.cc
diff --git a/sync/api/attachments/attachment_metadata_unittest.cc b/sync/api/attachments/attachment_metadata_unittest.cc
index 06477d0830c19bb449dcac670d33dabedb9b8a1f..a736b7eceb339e5d2d665627a0e9c8dd787982fd 100644
--- a/sync/api/attachments/attachment_metadata_unittest.cc
+++ b/sync/api/attachments/attachment_metadata_unittest.cc
@@ -11,8 +11,9 @@ namespace syncer {
 class AttachmentMetadataTest : public testing::Test {};
 
 TEST_F(AttachmentMetadataTest, Create) {
-  AttachmentId id = AttachmentId::Create();
   size_t size = 42;
+  uint32_t crc32c = 2349829;
+  AttachmentId id = AttachmentId::Create(size, crc32c);
   AttachmentMetadata metadata(id, size);

[pavely, 2015/03/07 00:07:25]

Now AttachmentMetadata has size both in Id and as separate field. Could you
leave TODO comment for me in attachment_metadata.h to sort it out?

[maniscalco, 2015/03/09 17:08:59]

Done (added TODO to attachment_metadata.h).

   EXPECT_EQ(metadata.GetId(), id);
   EXPECT_EQ(metadata.GetSize(), size);