[PA] Namespace migration (28 of N)

This CL moves *Scan's `StatsReporter` class into the `partition_alloc`
namespace.

No alias within the `base` namespace is provided, since that appears to
conflict with the various forward declarations of `StatsReporter` used
throughout *Scan. Instead, this CL elects to rewrite all users of
`StatsReporter` to reflect its new place under `::partition_alloc`.

Bug: 1288247
Change-Id: I502b34bf8868d543c197da5d96583b5c64153288
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3559049
Reviewed-by: Bartek Nowierski <bartekn@chromium.org>
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Commit-Queue: Kalvin Lee <kdlee@chromium.org>
Cr-Commit-Position: refs/heads/main@{#988998}

base/allocator/partition_alloc_support.cc

@@ -79,7 +79,7 @@ constexpr const char* MutatorIdToTracingString(
 }
 
 // Inject TRACE_EVENT_BEGIN/END, TRACE_COUNTER1, and UmaHistogramTimes.
-class StatsReporterImpl final : public StatsReporter {
+class StatsReporterImpl final : public partition_alloc::StatsReporter {
  public:
   void ReportTraceEvent(internal::StatsCollector::ScannerId id,
                         [[maybe_unused]] const PlatformThreadId tid,

base/allocator/partition_allocator/starscan/pcscan.cc

@@ -104,7 +104,7 @@ void PCScan::FinishScanForTesting() {
   PCScanInternal::Instance().FinishScanForTesting();  // IN-TEST
 }
 
-void PCScan::RegisterStatsReporter(StatsReporter* reporter) {
+void PCScan::RegisterStatsReporter(partition_alloc::StatsReporter* reporter) {
   PCScanInternal::Instance().RegisterStatsReporter(reporter);
 }
 

base/allocator/partition_allocator/starscan/pcscan.h

@@ -20,11 +20,13 @@
 // We currently disable it to improve the runtime.
 #define PA_STARSCAN_EAGER_DOUBLE_FREE_DETECTION_ENABLED 0
 
-namespace base {
+namespace partition_alloc {
 
 class StatsReporter;
 
-namespace internal {
+}  // namespace partition_alloc
+
+namespace base::internal {
 
 [[noreturn]] BASE_EXPORT NOINLINE NOT_TAIL_CALLED void DoubleFreeAttempt();
 
@@ -141,7 +143,7 @@ class BASE_EXPORT PCScan final {
   inline static PCScanScheduler& scheduler();
 
   // Registers reporting class.
-  static void RegisterStatsReporter(StatsReporter* reporter);
+  static void RegisterStatsReporter(partition_alloc::StatsReporter* reporter);
 
  private:
   class PCScanThread;
@@ -277,7 +279,6 @@ inline PCScanScheduler& PCScan::scheduler() {
   return instance.scheduler_;
 }
 
-}  // namespace internal
-}  // namespace base
+}  // namespace base::internal
 
 #endif  // BASE_ALLOCATOR_PARTITION_ALLOCATOR_STARSCAN_PCSCAN_H_

base/allocator/partition_allocator/starscan/pcscan_internal.cc

@@ -1306,7 +1306,7 @@ void PCScanInternal::Initialize(PCScan::InitConfig config) {
   scannable_roots_ = RootsMap();
   nonscannable_roots_ = RootsMap();
 
-  static StatsReporter s_no_op_reporter;
+  static partition_alloc::StatsReporter s_no_op_reporter;
   PCScan::Instance().RegisterStatsReporter(&s_no_op_reporter);
 
   // Don't initialize PCScanThread::Instance() as otherwise sandbox complains
@@ -1606,12 +1606,13 @@ void PCScanInternal::FinishScanForTesting() {
   current_task->RunFromScanner();
 }
 
-void PCScanInternal::RegisterStatsReporter(StatsReporter* reporter) {
+void PCScanInternal::RegisterStatsReporter(
+    partition_alloc::StatsReporter* reporter) {
   PA_DCHECK(reporter);
   stats_reporter_ = reporter;
 }
 
-StatsReporter& PCScanInternal::GetReporter() {
+partition_alloc::StatsReporter& PCScanInternal::GetReporter() {
   PA_DCHECK(stats_reporter_);
   return *stats_reporter_;
 }

base/allocator/partition_allocator/starscan/pcscan_internal.h

@@ -27,11 +27,7 @@ class StarScanSnapshot;
 
 }  // namespace partition_alloc::internal
 
-namespace base {
-
-class StatsReporter;
-
-namespace internal {
+namespace base::internal {
 
 class PCScanTask;
 
@@ -114,8 +110,8 @@ class PCScanInternal final {
   void ReinitForTesting(PCScan::InitConfig);                 // IN-TEST
   void FinishScanForTesting();                               // IN-TEST
 
-  void RegisterStatsReporter(StatsReporter* reporter);
-  StatsReporter& GetReporter();
+  void RegisterStatsReporter(partition_alloc::StatsReporter* reporter);
+  partition_alloc::StatsReporter& GetReporter();
 
  private:
   friend base::NoDestructor<PCScanInternal>;
@@ -149,14 +145,12 @@ class PCScanInternal final {
   const SimdSupport simd_support_;
 
   std::unique_ptr<WriteProtector> write_protector_;
-  StatsReporter* stats_reporter_ = nullptr;
+  partition_alloc::StatsReporter* stats_reporter_ = nullptr;
 
   bool is_initialized_ = false;
 };
 
-}  // namespace internal
-
-}  // namespace base
+}  // namespace base::internal
 
 // TODO(crbug.com/1288247): Remove this when migration is complete.
 namespace partition_alloc::internal {

base/allocator/partition_allocator/starscan/stats_collector.cc

@@ -25,7 +25,8 @@ base::TimeDelta StatsCollector::GetOverallTime() const {
                                         ScannerId::kOverall);
 }
 
-void StatsCollector::ReportTracesAndHists(StatsReporter& reporter) const {
+void StatsCollector::ReportTracesAndHists(
+    partition_alloc::StatsReporter& reporter) const {
   ReportTracesAndHistsImpl<Context::kMutator>(reporter, mutator_trace_events_);
   ReportTracesAndHistsImpl<Context::kScanner>(reporter, scanner_trace_events_);
   ReportSurvivalRate(reporter);
@@ -46,7 +47,7 @@ base::TimeDelta StatsCollector::GetTimeImpl(
 
 template <Context context>
 void StatsCollector::ReportTracesAndHistsImpl(
-    StatsReporter& reporter,
+    partition_alloc::StatsReporter& reporter,
     const DeferredTraceEventMap<context>& event_map) const {
   std::array<base::TimeDelta, static_cast<size_t>(IdType<context>::kNumIds)>
       accumulated_events{};
@@ -79,7 +80,8 @@ void StatsCollector::ReportTracesAndHistsImpl(
   }
 }
 
-void StatsCollector::ReportSurvivalRate(StatsReporter& reporter) const {
+void StatsCollector::ReportSurvivalRate(
+    partition_alloc::StatsReporter& reporter) const {
   const double survived_rate =
       static_cast<double>(survived_quarantine_size()) / quarantine_last_size_;
   reporter.ReportSurvivedQuarantineSize(survived_quarantine_size());
@@ -101,10 +103,10 @@ template base::TimeDelta StatsCollector::GetTimeImpl(
     IdType<Context::kScanner>) const;
 
 template void StatsCollector::ReportTracesAndHistsImpl(
-    StatsReporter& reporter,
+    partition_alloc::StatsReporter& reporter,
     const DeferredTraceEventMap<Context::kMutator>&) const;
 template void StatsCollector::ReportTracesAndHistsImpl(
-    StatsReporter& reporter,
+    partition_alloc::StatsReporter& reporter,
     const DeferredTraceEventMap<Context::kScanner>&) const;
 
 }  // namespace internal

base/allocator/partition_allocator/starscan/stats_collector.h

@@ -19,11 +19,11 @@
 #include "base/threading/platform_thread.h"
 #include "base/time/time.h"
 
-namespace base {
-
+namespace partition_alloc {
 class StatsReporter;
+}  // namespace partition_alloc
 
-namespace internal {
+namespace base::internal {
 
 #define FOR_ALL_PCSCAN_SCANNER_SCOPES(V) \
   V(Clear)                               \
@@ -133,7 +133,7 @@ class StatsCollector final {
   }
 
   base::TimeDelta GetOverallTime() const;
-  void ReportTracesAndHists(StatsReporter& reporter) const;
+  void ReportTracesAndHists(partition_alloc::StatsReporter& reporter) const;
 
  private:
   using MetadataString =
@@ -161,10 +161,10 @@ class StatsCollector final {
 
   template <Context context>
   void ReportTracesAndHistsImpl(
-      StatsReporter& reporter,
+      partition_alloc::StatsReporter& reporter,
       const DeferredTraceEventMap<context>& event_map) const;
 
-  void ReportSurvivalRate(StatsReporter& reporter) const;
+  void ReportSurvivalRate(partition_alloc::StatsReporter& reporter) const;
 
   DeferredTraceEventMap<Context::kMutator> mutator_trace_events_;
   DeferredTraceEventMap<Context::kScanner> scanner_trace_events_;
@@ -241,7 +241,6 @@ inline StatsCollector::MetadataString StatsCollector::ToUMAString(
 #undef FOR_ALL_PCSCAN_MUTATOR_SCOPES
 #undef FOR_ALL_PCSCAN_SCANNER_SCOPES
 
-}  // namespace internal
-}  // namespace base
+}  // namespace base::internal
 
 #endif  // BASE_ALLOCATOR_PARTITION_ALLOCATOR_STARSCAN_STATS_COLLECTOR_H_

base/allocator/partition_allocator/starscan/stats_reporter.h

@@ -9,29 +9,29 @@
 #include "base/threading/platform_thread.h"
 #include "base/time/time.h"
 
-namespace base {
+namespace partition_alloc {
 
 // StatsReporter is a wrapper to invoke TRACE_EVENT_BEGIN/END, TRACE_COUNTER1,
 // and UmaHistogramTimes. It is used to just remove trace_log and uma
 // dependencies from partition allocator.
 class StatsReporter {
  public:
-  virtual void ReportTraceEvent(internal::StatsCollector::ScannerId id,
-                                const PlatformThreadId tid,
-                                TimeTicks start_time,
-                                TimeTicks end_time) {}
-  virtual void ReportTraceEvent(internal::StatsCollector::MutatorId id,
-                                const PlatformThreadId tid,
-                                TimeTicks start_time,
-                                TimeTicks end_time) {}
+  virtual void ReportTraceEvent(base::internal::StatsCollector::ScannerId id,
+                                const base::PlatformThreadId tid,
+                                base::TimeTicks start_time,
+                                base::TimeTicks end_time) {}
+  virtual void ReportTraceEvent(base::internal::StatsCollector::MutatorId id,
+                                const base::PlatformThreadId tid,
+                                base::TimeTicks start_time,
+                                base::TimeTicks end_time) {}
 
   virtual void ReportSurvivedQuarantineSize(size_t survived_size) {}
 
   virtual void ReportSurvivedQuarantinePercent(double survivied_rate) {}
 
-  virtual void ReportStats(const char* stats_name, TimeDelta sample) {}
+  virtual void ReportStats(const char* stats_name, base::TimeDelta sample) {}
 };
 
-}  // namespace base
+}  // namespace partition_alloc
 
 #endif  // BASE_ALLOCATOR_PARTITION_ALLOCATOR_STARSCAN_STATS_REPORTER_H_