[Sync] Remove backend unrecoverable error handler

It was being used to allowed passing ownership of an error handler, but passing
a weak handle works just as well.

BUG=511235

Review URL: https://codereview.chromium.org/1275743002

Cr-Commit-Position: refs/heads/master@{#342384}

4 files changed, 25 insertions, 2 deletions

diff --git a/sync/util/mock_unrecoverable_error_handler.cc b/sync/util/mock_unrecoverable_error_handler.cc
index bfed1f1..3f34eca 100644
--- a/sync/util/mock_unrecoverable_error_handler.cc
+++ b/sync/util/mock_unrecoverable_error_handler.cc
@@ -7,7 +7,8 @@
 namespace syncer {
 
 MockUnrecoverableErrorHandler::MockUnrecoverableErrorHandler()
-    : invocation_count_(0) {
+    : invocation_count_(0),
+      weak_ptr_factory_(this) {
 }
 
 MockUnrecoverableErrorHandler::~MockUnrecoverableErrorHandler() {
@@ -23,4 +24,9 @@ int MockUnrecoverableErrorHandler::invocation_count() const {
   return invocation_count_;
 }
 
+base::WeakPtr<MockUnrecoverableErrorHandler>
+MockUnrecoverableErrorHandler::GetWeakPtr() {
+  return weak_ptr_factory_.GetWeakPtr();
+}
+
 }  // namespace syncer
diff --git a/sync/util/mock_unrecoverable_error_handler.h b/sync/util/mock_unrecoverable_error_handler.h
index aacde89..0d80fe9 100644
--- a/sync/util/mock_unrecoverable_error_handler.h
+++ b/sync/util/mock_unrecoverable_error_handler.h
@@ -8,6 +8,7 @@
 #include <string>
 
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "sync/internal_api/public/util/unrecoverable_error_handler.h"
 
 namespace syncer {
@@ -24,9 +25,13 @@ class MockUnrecoverableErrorHandler : public UnrecoverableErrorHandler {
   // Returns the number of times this handler has been invoked.
   int invocation_count() const;
 
+  base::WeakPtr<MockUnrecoverableErrorHandler> GetWeakPtr();
+
  private:
   int invocation_count_;
 
+  base::WeakPtrFactory<MockUnrecoverableErrorHandler> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(MockUnrecoverableErrorHandler);
 };
 
diff --git a/sync/util/test_unrecoverable_error_handler.cc b/sync/util/test_unrecoverable_error_handler.cc
index 4bdbf3d..14d39e6 100644
--- a/sync/util/test_unrecoverable_error_handler.cc
+++ b/sync/util/test_unrecoverable_error_handler.cc
@@ -8,7 +8,8 @@
 
 namespace syncer {
 
-TestUnrecoverableErrorHandler::TestUnrecoverableErrorHandler() {}
+TestUnrecoverableErrorHandler::TestUnrecoverableErrorHandler()
+    : weak_ptr_factory_(this) {}
 
 TestUnrecoverableErrorHandler::~TestUnrecoverableErrorHandler() {}
 
@@ -19,5 +20,10 @@ void TestUnrecoverableErrorHandler::OnUnrecoverableError(
       << from_here.function_name() << ": " << message;
 }
 
+base::WeakPtr<TestUnrecoverableErrorHandler>
+TestUnrecoverableErrorHandler::GetWeakPtr() {
+  return weak_ptr_factory_.GetWeakPtr();
+}
+
 }  // namespace syncer
 
diff --git a/sync/util/test_unrecoverable_error_handler.h b/sync/util/test_unrecoverable_error_handler.h
index ae0610c..1546783 100644
--- a/sync/util/test_unrecoverable_error_handler.h
+++ b/sync/util/test_unrecoverable_error_handler.h
@@ -6,6 +6,7 @@
 #define SYNC_INTERNAL_API_INCLUDES_TEST_UNRECOVERABLE_ERROR_HANDLER_H_
 
 #include "base/compiler_specific.h"
+#include "base/memory/weak_ptr.h"
 #include "sync/internal_api/public/util/unrecoverable_error_handler.h"
 
 namespace syncer {
@@ -19,6 +20,11 @@ class TestUnrecoverableErrorHandler : public UnrecoverableErrorHandler {
 
   void OnUnrecoverableError(const tracked_objects::Location& from_here,
                             const std::string& message) override;
+
+  base::WeakPtr<TestUnrecoverableErrorHandler> GetWeakPtr();
+
+ private:
+  base::WeakPtrFactory<TestUnrecoverableErrorHandler> weak_ptr_factory_;
 };
 
 }  // namespace syncer