services/tracing: Annotate code for static locking enforcement

Bug: 1138893
Change-Id: I9bb9f1c0115d7081795dfd69dee24cd93640392c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2485069
Commit-Queue: Andrew Shulaev <ddrone@google.com>
Reviewed-by: Eric Seckler <eseckler@chromium.org>
Cr-Commit-Position: refs/heads/master@{#819347}

services/tracing/public/cpp/perfetto/trace_event_data_source.cc

@@ -119,11 +119,14 @@ static_assert(
 
 // Helper class used to ensure no tasks are posted while
 // TraceEventDataSource::lock_ is held.
-class AutoLockWithDeferredTaskPosting {
+class SCOPED_LOCKABLE AutoLockWithDeferredTaskPosting {
  public:
   explicit AutoLockWithDeferredTaskPosting(base::Lock& lock)
+      EXCLUSIVE_LOCK_FUNCTION(lock)
       : autolock_(lock) {}
 
+  ~AutoLockWithDeferredTaskPosting() UNLOCK_FUNCTION() = default;
+
  private:
   // The ordering is important: |defer_task_posting_| must be destroyed
   // after |autolock_| to ensure the lock is not held when any deferred
@@ -159,7 +162,10 @@ TraceEventMetadataSource::~TraceEventMetadataSource() = default;
 void TraceEventMetadataSource::AddGeneratorFunction(
     JsonMetadataGeneratorFunction generator) {
   DCHECK(origin_task_runner_->RunsTasksInCurrentSequence());
+  {
+    base::AutoLock lock(lock_);
     json_generator_functions_.push_back(generator);
+  }
   // An EventBundle is created when nullptr is passed.
   GenerateJsonMetadataFromGenerator(generator, nullptr);
 }
@@ -167,14 +173,20 @@ void TraceEventMetadataSource::AddGeneratorFunction(
 void TraceEventMetadataSource::AddGeneratorFunction(
     MetadataGeneratorFunction generator) {
   DCHECK(origin_task_runner_->RunsTasksInCurrentSequence());
+  {
+    base::AutoLock lock(lock_);
     generator_functions_.push_back(generator);
+  }
   GenerateMetadataFromGenerator(generator);
 }
 
 void TraceEventMetadataSource::AddGeneratorFunction(
     PacketGeneratorFunction generator) {
   DCHECK(origin_task_runner_->RunsTasksInCurrentSequence());
+  {
+    base::AutoLock lock(lock_);
     packet_generator_functions_.push_back(generator);
+  }
   GenerateMetadataPacket(generator);
 }
 
@@ -282,7 +294,12 @@ TraceEventMetadataSource::GenerateLegacyMetadataDict() {
   DCHECK(!privacy_filtering_enabled_);
 
   auto merged_metadata = std::make_unique<base::DictionaryValue>();
-  for (auto& generator : json_generator_functions_) {
+  std::vector<JsonMetadataGeneratorFunction> json_generators;
+  {
+    base::AutoLock lock(lock_);
+    json_generators = json_generator_functions_;
+  }
+  for (auto& generator : json_generators) {
     std::unique_ptr<base::DictionaryValue> metadata_dict = generator.Run();
     if (!metadata_dict) {
       continue;

services/tracing/public/cpp/perfetto/trace_event_data_source.h

@@ -122,19 +122,20 @@ class COMPONENT_EXPORT(TRACING_CPP) TraceEventMetadataSource
   // TODO(crbug.com/1138893): Change annotations to GUARDED_BY
   base::Lock lock_;
   std::vector<JsonMetadataGeneratorFunction> json_generator_functions_
-      GUARDED_BY_FIXME(lock_);
-  std::vector<MetadataGeneratorFunction> generator_functions_
-      GUARDED_BY_FIXME(lock_);
+      GUARDED_BY(lock_);
+  std::vector<MetadataGeneratorFunction> generator_functions_ GUARDED_BY(lock_);
   std::vector<PacketGeneratorFunction> packet_generator_functions_
-      GUARDED_BY_FIXME(lock_);
+      GUARDED_BY(lock_);
 
-  const scoped_refptr<base::SequencedTaskRunner> origin_task_runner_;
+  const scoped_refptr<base::SequencedTaskRunner> origin_task_runner_
+      GUARDED_BY_FIXME(lock_);
 
-  std::unique_ptr<perfetto::TraceWriter> trace_writer_;
-  bool privacy_filtering_enabled_ = false;
-  std::string chrome_config_;
-  std::unique_ptr<base::trace_event::TraceConfig> parsed_chrome_config_;
-  bool emit_metadata_at_start_ = false;
+  std::unique_ptr<perfetto::TraceWriter> trace_writer_ GUARDED_BY_FIXME(lock_);
+  bool privacy_filtering_enabled_ GUARDED_BY_FIXME(lock_) = false;
+  std::string chrome_config_ GUARDED_BY(lock_);
+  std::unique_ptr<base::trace_event::TraceConfig> parsed_chrome_config_
+      GUARDED_BY(lock_);
+  bool emit_metadata_at_start_ GUARDED_BY(lock_) = false;
 
   DISALLOW_COPY_AND_ASSIGN(TraceEventMetadataSource);
 };