Update sync protos to use the new shared protoc gyp rules

chrome/chrome.gyp

Index: chrome/chrome.gyp
diff --git a/chrome/chrome.gyp b/chrome/chrome.gyp
index 9b220b3686ed01e25d3f1a74a13754e98d4f8bb7..43769e75531c5a69faa54cdc93ca5f7c5aac95fc 100644
--- a/chrome/chrome.gyp
+++ b/chrome/chrome.gyp
@@ -542,18 +542,18 @@
         '../third_party/icu/icu.gyp:icuuc',
         '../third_party/sqlite/sqlite.gyp:sqlite',
         'app/policy/cloud_policy_codegen.gyp:policy',
-        'browser/sync/protocol/sync_proto.gyp:sync_proto_cpp',
+        'browser/sync/protocol/sync_proto.gyp:sync_proto',
         'common_constants',
         'common_net',
         'sync',
         'sync_notifier',
       ],
       'export_dependent_settings': [
-        'browser/sync/protocol/sync_proto.gyp:sync_proto_cpp',
+        'browser/sync/protocol/sync_proto.gyp:sync_proto',
         'sync',
       ],
       # This target exports a hard dependency because syncapi.h includes
-      # generated proto header files from sync_proto_cpp.
+      # generated proto header files from sync_proto.
       'hard_dependency': 1,

[TVL, 2011/08/19 13:05:21]

This seems like an odd ripple.  But maybe I just need more coffee before it
makes sense.

     },
     {
@@ -577,15 +577,15 @@
       ],
       'dependencies': [
         '../base/base.gyp:base',
-        'browser/sync/protocol/sync_proto.gyp:sync_proto_cpp',
+        'browser/sync/protocol/sync_proto.gyp:sync_proto',
         'sync',
       ],
       'export_dependent_settings': [
         '../base/base.gyp:base',
-        'browser/sync/protocol/sync_proto.gyp:sync_proto_cpp',
+        'browser/sync/protocol/sync_proto.gyp:sync_proto',
         'sync',
       ],
-      # Even though this target depends on sync_proto_cpp, it doesn't
+      # Even though this target depends on sync_proto, it doesn't
       # need to export a hard dependency since we explicitly avoid
       # including the generated proto header files from this target's
       # header files.
@@ -744,15 +744,15 @@
         '../base/base.gyp:base',
         '../crypto/crypto.gyp:crypto',
         '../skia/skia.gyp:skia',
-        'browser/sync/protocol/sync_proto.gyp:sync_proto_cpp',
+        'browser/sync/protocol/sync_proto.gyp:sync_proto',
       ],
       'export_dependent_settings': [
         '../base/base.gyp:base',
         '../crypto/crypto.gyp:crypto',
-        'browser/sync/protocol/sync_proto.gyp:sync_proto_cpp',
+        'browser/sync/protocol/sync_proto.gyp:sync_proto',
       ],
       # This target exports a hard dependency because its header files include
-      # protobuf header files from sync_proto_cpp.
+      # protobuf header files from sync_proto.
       'hard_dependency': 1,
       'conditions': [
         ['OS=="win"', {