[USS] Rename the SharedModelTypeProcessor

This CL renames the class to ClientTagBasesModelTypeProcessor that
 a) does not make the impression that its instance is shared
 b) uses a specific trait that distinguish this from other
    ModelTypeProcessors.

Bug: none
Change-Id: Ib5b3d9bb746a5667345dca07fe2a2306d315fca8
Reviewed-on: https://chromium-review.googlesource.com/951245Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Commit-Queue: Jan Krcal <jkrcal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541398}

components/sync/BUILD.gn

@@ -424,6 +424,8 @@ jumbo_static_library("sync") {
     "model/time.h",
     "model_impl/accumulating_metadata_change_list.cc",
     "model_impl/accumulating_metadata_change_list.h",
+    "model_impl/client_tag_based_model_type_processor.cc",
+    "model_impl/client_tag_based_model_type_processor.h",
     "model_impl/in_memory_metadata_change_list.cc",
     "model_impl/in_memory_metadata_change_list.h",
     "model_impl/model_type_store_backend.cc",
@@ -434,8 +436,6 @@ jumbo_static_library("sync") {
     "model_impl/passthrough_metadata_change_list.h",
     "model_impl/processor_entity_tracker.cc",
     "model_impl/processor_entity_tracker.h",
-    "model_impl/shared_model_type_processor.cc",
-    "model_impl/shared_model_type_processor.h",
     "model_impl/sync_metadata_store_change_list.cc",
     "model_impl/sync_metadata_store_change_list.h",
     "protocol/proto_enum_conversions.cc",
@@ -874,11 +874,11 @@ source_set("unit_tests") {
     "model/sync_error_unittest.cc",
     "model/sync_merge_result_unittest.cc",
     "model_impl/accumulating_metadata_change_list_unittest.cc",
+    "model_impl/client_tag_based_model_type_processor_unittest.cc",
     "model_impl/model_type_store_backend_unittest.cc",
     "model_impl/model_type_store_impl_unittest.cc",
     "model_impl/passthrough_metadata_change_list_unittest.cc",
     "model_impl/processor_entity_tracker_unittest.cc",
-    "model_impl/shared_model_type_processor_unittest.cc",
     "protocol/proto_enum_conversions_unittest.cc",
     "protocol/proto_value_conversions_unittest.cc",
     "syncable/change_record_unittest.cc",

components/sync/model/model_type_change_processor.cc

@@ -4,7 +4,7 @@
 
 #include "components/sync/model/model_type_change_processor.h"
 
-#include "components/sync/model_impl/shared_model_type_processor.h"
+#include "components/sync/model_impl/client_tag_based_model_type_processor.h"
 
 namespace syncer {
 
@@ -13,7 +13,7 @@ std::unique_ptr<ModelTypeChangeProcessor> ModelTypeChangeProcessor::Create(
     const base::RepeatingClosure& dump_stack,
     ModelType type,
     ModelTypeSyncBridge* bridge) {
-  return std::make_unique<SharedModelTypeProcessor>(
+  return std::make_unique<ClientTagBasedModelTypeProcessor>(
       type, bridge, dump_stack, CommitOnlyTypes().Has(type));
 }
 

components/sync/model/model_type_debug_info.cc

@@ -19,13 +19,15 @@ namespace syncer {
 
 namespace {
 
-SharedModelTypeProcessor* GetProcessorFromBridge(ModelTypeSyncBridge* bridge) {
+ClientTagBasedModelTypeProcessor* GetProcessorFromBridge(
+    ModelTypeSyncBridge* bridge) {
   ModelTypeChangeProcessor* processor = bridge->change_processor();
   if (processor == nullptr) {
-    LOG(WARNING) << "SharedModelTypeProcessor destroyed before debug info was "
-                    "retrieved.";
+    LOG(WARNING)
+        << "ClientTagBasedModelTypeProcessor destroyed before debug info was "
+           "retrieved.";
   }
-  return static_cast<SharedModelTypeProcessor*>(processor);
+  return static_cast<ClientTagBasedModelTypeProcessor*>(processor);
 }
 
 }  // namespace
@@ -35,7 +37,7 @@ void ModelTypeDebugInfo::GetAllNodes(
     const base::Callback<void(const ModelType, std::unique_ptr<ListValue>)>&
         callback,
     ModelTypeSyncBridge* bridge) {
-  SharedModelTypeProcessor* processor = GetProcessorFromBridge(bridge);
+  ClientTagBasedModelTypeProcessor* processor = GetProcessorFromBridge(bridge);
   if (processor) {
     bridge->GetAllData(base::Bind(&ModelTypeDebugInfo::MergeDataWithMetadata,
                                   base::Unretained(processor), callback));
@@ -46,7 +48,7 @@ void ModelTypeDebugInfo::GetAllNodes(
 void ModelTypeDebugInfo::GetStatusCounters(
     const base::Callback<void(ModelType, const StatusCounters&)>& callback,
     ModelTypeSyncBridge* bridge) {
-  SharedModelTypeProcessor* processor = GetProcessorFromBridge(bridge);
+  ClientTagBasedModelTypeProcessor* processor = GetProcessorFromBridge(bridge);
   if (processor) {
     StatusCounters counters;
     counters.num_entries_and_tombstones = processor->entities_.size();
@@ -62,7 +64,7 @@ void ModelTypeDebugInfo::GetStatusCounters(
 // static
 void ModelTypeDebugInfo::RecordMemoryUsageHistogram(
     ModelTypeSyncBridge* bridge) {
-  SharedModelTypeProcessor* processor = GetProcessorFromBridge(bridge);
+  ClientTagBasedModelTypeProcessor* processor = GetProcessorFromBridge(bridge);
   size_t memory_usage = processor->EstimateMemoryUsage();
   SyncRecordMemoryKbHistogram(kModelTypeMemoryHistogramPrefix, processor->type_,
                               memory_usage);
@@ -72,7 +74,7 @@ ModelTypeDebugInfo::ModelTypeDebugInfo() {}
 
 // static
 void ModelTypeDebugInfo::MergeDataWithMetadata(
-    SharedModelTypeProcessor* processor,
+    ClientTagBasedModelTypeProcessor* processor,
     const base::Callback<void(const ModelType, std::unique_ptr<ListValue>)>&
         callback,
     std::unique_ptr<DataBatch> batch) {

components/sync/model/model_type_debug_info.h

@@ -11,14 +11,14 @@
 #include "base/values.h"
 #include "components/sync/base/model_type.h"
 #include "components/sync/model/model_type_sync_bridge.h"
-#include "components/sync/model_impl/shared_model_type_processor.h"
+#include "components/sync/model_impl/client_tag_based_model_type_processor.h"
 
 namespace syncer {
 
 // This class holds static functions used for extracting debug information for a
 // model type. They should be run on the model thread. These functions are
 // static so they can be posted to from the UI thread, and they live inside a
-// class because it is a friend class to SharedModelTypeProcessor.
+// class because it is a friend class to ClientTagBasedModelTypeProcessor.
 class ModelTypeDebugInfo {
  public:
   // Returns a ListValue representing all nodes for the type to |callback|.
@@ -46,7 +46,7 @@ class ModelTypeDebugInfo {
   // function will merge real data from |batch| with metadata extracted from
   // the |processor|, then pass it all to |callback|.
   static void MergeDataWithMetadata(
-      SharedModelTypeProcessor* processor,
+      ClientTagBasedModelTypeProcessor* processor,
       const base::Callback<void(const ModelType,
                                 std::unique_ptr<base::ListValue>)>& callback,
       std::unique_ptr<DataBatch> batch);

components/sync/model_impl/shared_model_type_processor.h → components/sync/model_impl/client_tag_based_model_type_processor.h

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef COMPONENTS_SYNC_MODEL_IMPL_SHARED_MODEL_TYPE_PROCESSOR_H_
-#define COMPONENTS_SYNC_MODEL_IMPL_SHARED_MODEL_TYPE_PROCESSOR_H_
+#ifndef COMPONENTS_SYNC_MODEL_IMPL_CLIENT_TAG_BASED_MODEL_TYPE_PROCESSOR_H_
+#define COMPONENTS_SYNC_MODEL_IMPL_CLIENT_TAG_BASED_MODEL_TYPE_PROCESSOR_H_
 
 #include <map>
 #include <memory>
@@ -34,16 +34,17 @@ class ProcessorEntityTracker;
 
 // A sync component embedded on the model type's thread that tracks entity
 // metadata in the model store and coordinates communication between sync and
-// model type threads. See //docs/sync/uss/shared_model_type_processor.md for a
-// more thorough description.
-class SharedModelTypeProcessor : public ModelTypeProcessor,
-                                 public ModelTypeChangeProcessor {
+// model type threads. See
+// //docs/sync/uss/client_tag_based_model_type_processor.md for a more thorough
+// description.
+class ClientTagBasedModelTypeProcessor : public ModelTypeProcessor,
+                                         public ModelTypeChangeProcessor {
  public:
-  SharedModelTypeProcessor(ModelType type,
-                           ModelTypeSyncBridge* bridge,
-                           const base::RepeatingClosure& dump_stack,
-                           bool commit_only);
-  ~SharedModelTypeProcessor() override;
+  ClientTagBasedModelTypeProcessor(ModelType type,
+                                   ModelTypeSyncBridge* bridge,
+                                   const base::RepeatingClosure& dump_stack,
+                                   bool commit_only);
+  ~ClientTagBasedModelTypeProcessor() override;
 
   // Whether the processor is allowing changes to its model type. If this is
   // false, the bridge should not allow any changes to its data.
@@ -84,7 +85,7 @@ class SharedModelTypeProcessor : public ModelTypeProcessor,
 
  private:
   friend class ModelTypeDebugInfo;
-  friend class SharedModelTypeProcessorTest;
+  friend class ClientTagBasedModelTypeProcessorTest;
 
   // Returns true if the model is ready or encountered an error.
   bool IsModelReadyOrError() const;
@@ -270,11 +271,11 @@ class SharedModelTypeProcessor : public ModelTypeProcessor,
   SEQUENCE_CHECKER(sequence_checker_);
 
   // WeakPtrFactory for this processor which will be sent to sync thread.
-  base::WeakPtrFactory<SharedModelTypeProcessor> weak_ptr_factory_;
+  base::WeakPtrFactory<ClientTagBasedModelTypeProcessor> weak_ptr_factory_;
 
-  DISALLOW_COPY_AND_ASSIGN(SharedModelTypeProcessor);
+  DISALLOW_COPY_AND_ASSIGN(ClientTagBasedModelTypeProcessor);
 };
 
 }  // namespace syncer
 
-#endif  // COMPONENTS_SYNC_MODEL_IMPL_SHARED_MODEL_TYPE_PROCESSOR_H_
+#endif  // COMPONENTS_SYNC_MODEL_IMPL_CLIENT_TAG_BASED_MODEL_TYPE_PROCESSOR_H_

docs/README.md

@@ -127,7 +127,7 @@ used when committed.
 *   [base::Optional](optional.md) - How to use `base::Optional` in C++ code.
 *   [Using the Origin Trials Framework](origin_trials_integration.md) - A
     framework for conditionally enabling experimental APIs for testing.
-*   [`SharedModelTypeProcessor` in Unified Sync and Storage](sync/uss/shared_model_type_processor.md) -
+*   [`ClientTagBasedModelTypeProcessor` in Unified Sync and Storage](sync/uss/client_tag_based_model_type_processor.md) -
     Notes on the central data structure used in Chrome Sync.
 *   [Chrome Sync's Model API](sync/model_api.md) - Data models used for syncing
     information across devices using Chrome Sync.

docs/sync/uss/shared_model_type_processor.md → docs/sync/uss/client_tag_based_model_type_processor.md

-# SharedModelTypeProcessor
+# ClientTagBasedModelTypeProcessor
 
-The [`SharedModelTypeProcessor`][SMTP] is a crucial piece of the USS codepath.
+The [`ClientTagBasedModelTypeProcessor`][SMTP] is a crucial piece of the USS codepath.
 It lives on the model thread and performs the tracking of sync metadata for the
 [`ModelTypeSyncBridge`][MTSB] that owns it by implementing the
 [`ModelTypeChangeProcessor`][MTCP] interface, as well as sending commit requests
@@ -8,7 +8,7 @@ to the [`ModelTypeWorker`][MTW] on the sync thread via the [`CommitQueue`][CQ]
 interface and receiving updates from the same worker via the
 [`ModelTypeProcessor`][MTP] interface.
 
-[SMTP]: https://cs.chromium.org/chromium/src/components/sync/model_impl/shared_model_type_processor.h
+[SMTP]: https://cs.chromium.org/chromium/src/components/sync/model_impl/client_tag_based_model_type_processor.h
 [MTSB]: https://cs.chromium.org/chromium/src/components/sync/model/model_type_sync_bridge.h
 [MTCP]: https://cs.chromium.org/chromium/src/components/sync/model/model_type_change_processor.h
 [MTW]: https://cs.chromium.org/chromium/src/components/sync/engine_impl/model_type_worker.h