Completely rewrite the PpdProvider/PpdCache to use the SCS backend. Along the way, clean it up a l…

components/sync/protocol/printer_specifics.proto

Index: components/sync/protocol/printer_specifics.proto
diff --git a/components/sync/protocol/printer_specifics.proto b/components/sync/protocol/printer_specifics.proto
index e0881b71dd56b355ff42511fa9a22ba9d084f94e..05313e7d3afcce0c8377647975bcd5c4ae731536 100644
--- a/components/sync/protocol/printer_specifics.proto
+++ b/components/sync/protocol/printer_specifics.proto
@@ -18,9 +18,12 @@ message PrinterPPDReference {
   // Url for user provided file.  Overrides other fields.
   optional string user_supplied_ppd_url = 1;
 
-  // Make and model to reference into PPD Server.
-  optional string effective_manufacturer = 2;
-  optional string effective_model = 3;
+  // Retired fields
+  reserved 2 to 3;

[skau, 2017/02/01 23:45:14]

Sorry, it looks like they didn't update the proto compiler >:( You'll want to
change this back to what you had before.  This is what is breaking the android
tests.

[skym, 2017/02/02 00:02:28]

Can use the option [deprecated = true] to make intention more clear as well.
This is currently our general best practice for sync protos.

[Carlson, 2017/02/02 01:48:58]

Done.

+
+  // String identifying the type of printer, used to look up a ppd to drive the
+  // printer.
+  optional string effective_make_and_model = 4;
 }
 
 message PrinterSpecifics {