Revert of Delete class ScopedPtrCollection. Replaced with vector of unique_ptr. (patchset #1 id:1 of https://codereview.webrtc.org/2808463002/ )

Reason for revert:
Deleting scopedptrcollection.h broke an internal project.

Original issue's description:
> Delete class ScopedPtrCollection. Replaced with vector of unique_ptr.
>
> BUG=None
>
> Review-Url: https://codereview.webrtc.org/2808463002
> Cr-Commit-Position: refs/heads/master@{#17605}
> Committed: 188596f20f

TBR=pthatcher@webrtc.org,kwiberg@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=None

Review-Url: https://codereview.webrtc.org/2812553002
Cr-Commit-Position: refs/heads/master@{#17607}

webrtc/base/BUILD.gn

@@ -508,6 +508,7 @@ rtc_static_library("rtc_base") {
       "optionsfile.cc",
       "optionsfile.h",
       "rollingaccumulator.h",
+      "scopedptrcollection.h",
       "sslroots.h",
       "testbase64.h",
       "testclient.cc",
@@ -868,6 +869,7 @@ if (rtc_include_tests) {
       "rollingaccumulator_unittest.cc",
       "rtccertificate_unittest.cc",
       "rtccertificategenerator_unittest.cc",
+      "scopedptrcollection_unittest.cc",
       "sha1digest_unittest.cc",
       "sharedexclusivelock_unittest.cc",
       "signalthread_unittest.cc",

webrtc/base/criticalsection_unittest.cc

@@ -18,6 +18,7 @@
 #include "webrtc/base/event.h"
 #include "webrtc/base/gunit.h"
 #include "webrtc/base/platform_thread.h"
+#include "webrtc/base/scopedptrcollection.h"
 #include "webrtc/base/thread.h"
 
 namespace rtc {
@@ -198,13 +199,13 @@ struct CompareAndSwapOp {
   static int AtomicOp(int* i) { return AtomicOps::CompareAndSwap(i, 0, 1); }
 };
 
-void StartThreads(std::vector<std::unique_ptr<Thread>>* threads,
+void StartThreads(ScopedPtrCollection<Thread>* threads,
                   MessageHandler* handler) {
   for (int i = 0; i < kNumThreads; ++i) {
-    std::unique_ptr<Thread> thread(new Thread());
+    Thread* thread = new Thread();
     thread->Start();
     thread->Post(RTC_FROM_HERE, handler);
-    threads->push_back(std::move(thread));
+    threads->PushBack(thread);
   }
 }
 
@@ -247,7 +248,7 @@ TEST(AtomicOpsTest, SimplePtr) {
 TEST(AtomicOpsTest, Increment) {
   // Create and start lots of threads.
   AtomicOpRunner<IncrementOp, UniqueValueVerifier> runner(0);
-  std::vector<std::unique_ptr<Thread>> threads;
+  ScopedPtrCollection<Thread> threads;
   StartThreads(&threads, &runner);
   runner.SetExpectedThreadCount(kNumThreads);
 
@@ -260,7 +261,7 @@ TEST(AtomicOpsTest, Decrement) {
   // Create and start lots of threads.
   AtomicOpRunner<DecrementOp, UniqueValueVerifier> runner(
       kOperationsToRun * kNumThreads);
-  std::vector<std::unique_ptr<Thread>> threads;
+  ScopedPtrCollection<Thread> threads;
   StartThreads(&threads, &runner);
   runner.SetExpectedThreadCount(kNumThreads);
 
@@ -272,7 +273,7 @@ TEST(AtomicOpsTest, Decrement) {
 TEST(AtomicOpsTest, CompareAndSwap) {
   // Create and start lots of threads.
   AtomicOpRunner<CompareAndSwapOp, CompareAndSwapVerifier> runner(0);
-  std::vector<std::unique_ptr<Thread>> threads;
+  ScopedPtrCollection<Thread> threads;
   StartThreads(&threads, &runner);
   runner.SetExpectedThreadCount(kNumThreads);
 
@@ -284,7 +285,7 @@ TEST(AtomicOpsTest, CompareAndSwap) {
 TEST(GlobalLockTest, Basic) {
   // Create and start lots of threads.
   LockRunner<GlobalLock> runner;
-  std::vector<std::unique_ptr<Thread>> threads;
+  ScopedPtrCollection<Thread> threads;
   StartThreads(&threads, &runner);
   runner.SetExpectedThreadCount(kNumThreads);
 
@@ -296,7 +297,7 @@ TEST(GlobalLockTest, Basic) {
 TEST(CriticalSectionTest, Basic) {
   // Create and start lots of threads.
   LockRunner<CriticalSectionLock> runner;
-  std::vector<std::unique_ptr<Thread>> threads;
+  ScopedPtrCollection<Thread> threads;
   StartThreads(&threads, &runner);
   runner.SetExpectedThreadCount(kNumThreads);
 

webrtc/base/scopedptrcollection.h

@@ -0,0 +1,61 @@
+/*
+ *  Copyright 2014 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Stores a collection of pointers that are deleted when the container is
+// destructed.
+
+#ifndef WEBRTC_BASE_SCOPEDPTRCOLLECTION_H_
+#define WEBRTC_BASE_SCOPEDPTRCOLLECTION_H_
+
+#include <stddef.h>
+
+#include <algorithm>
+#include <vector>
+
+#include "webrtc/base/constructormagic.h"
+
+namespace rtc {
+
+template<class T>
+class ScopedPtrCollection {
+ public:
+  typedef std::vector<T*> VectorT;
+
+  ScopedPtrCollection() { }
+  ~ScopedPtrCollection() {
+    for (typename VectorT::iterator it = collection_.begin();
+         it != collection_.end(); ++it) {
+      delete *it;
+    }
+  }
+
+  const VectorT& collection() const { return collection_; }
+  void Reserve(size_t size) {
+    collection_.reserve(size);
+  }
+  void PushBack(T* t) {
+    collection_.push_back(t);
+  }
+
+  // Remove |t| from the collection without deleting it.
+  void Remove(T* t) {
+    collection_.erase(std::remove(collection_.begin(), collection_.end(), t),
+                      collection_.end());
+  }
+
+ private:
+  VectorT collection_;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(ScopedPtrCollection);
+};
+
+}  // namespace rtc
+
+#endif  // WEBRTC_BASE_SCOPEDPTRCOLLECTION_H_

webrtc/base/scopedptrcollection_unittest.cc

@@ -0,0 +1,76 @@
+/*
+ *  Copyright 2014 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <memory>
+
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/base/scopedptrcollection.h"
+#include "webrtc/base/gunit.h"
+
+namespace rtc {
+
+namespace {
+
+class InstanceCounter {
+ public:
+  explicit InstanceCounter(int* num_instances)
+      : num_instances_(num_instances) {
+    ++(*num_instances_);
+  }
+  ~InstanceCounter() {
+    --(*num_instances_);
+  }
+
+ private:
+  int* num_instances_;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(InstanceCounter);
+};
+
+}  // namespace
+
+class ScopedPtrCollectionTest : public testing::Test {
+ protected:
+  ScopedPtrCollectionTest()
+      : num_instances_(0),
+      collection_(new ScopedPtrCollection<InstanceCounter>()) {
+  }
+
+  int num_instances_;
+  std::unique_ptr<ScopedPtrCollection<InstanceCounter> > collection_;
+};
+
+TEST_F(ScopedPtrCollectionTest, PushBack) {
+  EXPECT_EQ(0u, collection_->collection().size());
+  EXPECT_EQ(0, num_instances_);
+  const int kNum = 100;
+  for (int i = 0; i < kNum; ++i) {
+    collection_->PushBack(new InstanceCounter(&num_instances_));
+  }
+  EXPECT_EQ(static_cast<size_t>(kNum), collection_->collection().size());
+  EXPECT_EQ(kNum, num_instances_);
+  collection_.reset();
+  EXPECT_EQ(0, num_instances_);
+}
+
+TEST_F(ScopedPtrCollectionTest, Remove) {
+  InstanceCounter* ic = new InstanceCounter(&num_instances_);
+  collection_->PushBack(ic);
+  EXPECT_EQ(1u, collection_->collection().size());
+  collection_->Remove(ic);
+  EXPECT_EQ(1, num_instances_);
+  collection_.reset();
+  EXPECT_EQ(1, num_instances_);
+  delete ic;
+  EXPECT_EQ(0, num_instances_);
+}
+
+
+}  // namespace rtc