Revert "Track thread activities in order to diagnose hangs."

base/debug/activity_analyzer.h

Index: base/debug/activity_analyzer.h
diff --git a/base/debug/activity_analyzer.h b/base/debug/activity_analyzer.h
deleted file mode 100644
index 5333de29166ed2d039c82f35b63b89d65e518ce2..0000000000000000000000000000000000000000
--- a/base/debug/activity_analyzer.h
+++ /dev/null
@@ -1,159 +0,0 @@
-// Copyright 2016 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef BASE_DEBUG_ACTIVITY_ANALYZER_H_
-#define BASE_DEBUG_ACTIVITY_ANALYZER_H_
-
-#include <map>
-#include <memory>
-#include <set>
-
-#include "base/base_export.h"
-#include "base/debug/activity_tracker.h"
-
-namespace base {
-namespace debug {
-
-// This class provides analysis of data captured from a ThreadActivityTracker.
-// When created, it takes a snapshot of the data held by the tracker and
-// makes that information available to other code.
-class BASE_EXPORT ThreadActivityAnalyzer {
- public:
-  using Activity = ThreadActivityTracker::Activity;
-  using ActivitySnapshot = ThreadActivityTracker::ActivitySnapshot;
-
-  // This class provides keys that uniquely identify a thread, even across
-  // multiple processes.
-  class ThreadKey {
-   public:
-    ThreadKey(int64_t pid, int64_t tid) : pid_(pid), tid_(tid) {}
-
-    bool operator<(const ThreadKey& rhs) const {
-      if (pid_ != rhs.pid_)
-        return pid_ < rhs.pid_;
-      return tid_ < rhs.tid_;
-    }
-
-    bool operator==(const ThreadKey& rhs) const {
-      return (pid_ == rhs.pid_ && tid_ == rhs.tid_);
-    }
-
-   private:
-    int64_t pid_;
-    int64_t tid_;
-  };
-
-  // Creates an analyzer for an existing activity |tracker|. A snapshot is taken
-  // immediately and the tracker is not referenced again.
-  explicit ThreadActivityAnalyzer(const ThreadActivityTracker& tracker);
-
-  // Creates an analyzer for a block of memory currently or previously in-use
-  // by an activity-tracker. A snapshot is taken immediately and the memory
-  // is not referenced again.
-  ThreadActivityAnalyzer(void* base, size_t size);
-
-  // Creates an analyzer for a block of memory held within a persistent-memory
-  // |allocator| at the given |reference|. A snapshot is taken immediately and
-  // the memory is not referenced again.
-  ThreadActivityAnalyzer(PersistentMemoryAllocator* allocator,
-                         PersistentMemoryAllocator::Reference reference);
-
-  ~ThreadActivityAnalyzer();
-
-  // Returns true iff the contained data is valid. Results from all other
-  // methods are undefined if this returns false.
-  bool IsValid() { return activity_snapshot_valid_; }
-
-  // Gets the name of the thread.
-  const std::string& GetThreadName() {
-    return activity_snapshot_.thread_name;
-  }
-
-  // Gets the TheadKey for this thread.
-  ThreadKey GetThreadKey() {
-    return ThreadKey(activity_snapshot_.process_id,
-                     activity_snapshot_.thread_id);
-  }
-
- private:
-  friend class GlobalActivityAnalyzer;
-
-  // The snapshot of the activity tracker taken at the moment of construction.
-  ActivitySnapshot activity_snapshot_;
-
-  // Flag indicating if the snapshot data is valid.
-  bool activity_snapshot_valid_;
-
-  // A reference into a persistent memory allocator, used by the global
-  // analyzer to know where this tracker came from.
-  PersistentMemoryAllocator::Reference allocator_reference_ = 0;
-
-  DISALLOW_COPY_AND_ASSIGN(ThreadActivityAnalyzer);
-};
-
-
-// This class manages analyzers for all known processes and threads as stored
-// in a persistent memory allocator. It supports retrieval of them through
-// iteration and directly using a ThreadKey, which allows for cross-references
-// to be resolved.
-// Note that though atomic snapshots are used and everything has its snapshot
-// taken at the same time, the multi-snapshot itself is not atomic and thus may
-// show small inconsistencies between threads if attempted on a live system.
-class BASE_EXPORT GlobalActivityAnalyzer {
- public:
-  using ThreadKey = ThreadActivityAnalyzer::ThreadKey;
-
-  // Creates a global analyzer from a persistent memory allocator.
-  explicit GlobalActivityAnalyzer(
-      std::unique_ptr<PersistentMemoryAllocator> allocator);
-
-  ~GlobalActivityAnalyzer();
-
-#if !defined(OS_NACL)
-  // Creates a global analyzer using the contents of a file given in
-  // |file_path|.
-  static std::unique_ptr<GlobalActivityAnalyzer> CreateWithFile(
-      const FilePath& file_path);
-#endif  // !defined(OS_NACL)
-
-  // Iterates over all known analyzers or returns null if there are no more.
-  // Ownership stays with the global analyzer object and all existing analyzer
-  // pointers are invalidated when GetFirstAnalyzer() is called.
-  ThreadActivityAnalyzer* GetFirstAnalyzer();
-  ThreadActivityAnalyzer* GetNextAnalyzer();
-
-  // Gets the analyzer for a specific thread or null if there is none.
-  // Ownership stays with the global analyzer object.
-  ThreadActivityAnalyzer* GetAnalyzerForThread(const ThreadKey& key);
-
- private:
-  using AnalyzerMap =
-      std::map<ThreadKey, std::unique_ptr<ThreadActivityAnalyzer>>;
-
-  // Finds, creates, and indexes analyzers for all known processes and threads.
-  void PrepareAllAnalyzers();
-
-  // The persistent memory allocator holding all tracking data.
-  std::unique_ptr<PersistentMemoryAllocator> allocator_;
-
-  // The iterator for finding tracking information in the allocator.
-  PersistentMemoryAllocator::Iterator allocator_iterator_;
-
-  // A set of all tracker memory references found within the allocator.
-  std::set<PersistentMemoryAllocator::Reference> tracker_references_;
-
-  // A map, keyed by ThreadKey, of all valid activity analyzers.
-  AnalyzerMap analyzers_;
-
-  // The iterator within the analyzers_ map for returning analyzers through
-  // first/next iteration.
-  AnalyzerMap::iterator analyzers_iterator_;
-
-  DISALLOW_COPY_AND_ASSIGN(GlobalActivityAnalyzer);
-};
-
-}  // namespace debug
-}  // namespace base
-
-#endif  // BASE_DEBUG_ACTIVITY_ANALYZER_H_