Sync/Valgrind: Add gmock printers for SyncChange, SyncData, SyncError.

chrome/browser/sync/api/sync_error.cc

Index: chrome/browser/sync/api/sync_error.cc
diff --git a/chrome/browser/sync/api/sync_error.cc b/chrome/browser/sync/api/sync_error.cc
index 453a920d70afcd9fef531775a3594b504b56b5c4..0023a05362e893089cb4f1498579680d551b843e 100644
--- a/chrome/browser/sync/api/sync_error.cc
+++ b/chrome/browser/sync/api/sync_error.cc
@@ -4,8 +4,11 @@
 
 #include "chrome/browser/sync/api/sync_error.h"
 
+#include <ostream>
+
 #include "base/location.h"
 #include "base/logging.h"
+#include "chrome/browser/sync/syncable/model_type.h"
 
 SyncError::SyncError() {
   Clear();
@@ -83,6 +86,15 @@ syncable::ModelType SyncError::type() const {
   return type_;
 }
 
+std::string SyncError::ToString() const {
+  if (IsSet()) {
+    return "{ location: " + location_->ToString() + ", type: " +
+        syncable::ModelTypeToString(type()) + ", message: " + message() + "}";
+  }
+
+  return "<Unset SyncError>";
+}
+
 void SyncError::PrintLogError() const {
   LAZY_STREAM(logging::LogMessage(location_->file_name(),
                                   location_->line_number(),
@@ -90,3 +102,7 @@ void SyncError::PrintLogError() const {
               LOG_IS_ON(ERROR))
       << syncable::ModelTypeToString(type_) << " Sync Error: " << message_;
 }
+
+void PrintTo(const SyncError& sync_error, std::ostream* os) {
+  *os << sync_error.ToString();
+}