Fix size_t and remove base class.

Previous size_t changes broke the build - just using size_t now
for all stats.

Also remove the base class. The idea with that was to allow this
pool to be used with the unsigned base classes in the mdns code.
However, it looks like it's causing memory bloat despite the fact
that nothing actually uses that base class. So it looks like
maybe we just need to refactor to mdns.

src/system/SystemObject.h

@@ -197,26 +197,6 @@ union ObjectArena
     ALIGN uAlign;
 };
 
-/**
- *  @class ObjectPoolBase
- *
- *  @brief
- *    This is the abstract base class for Static and Dynamic ObjectPool objects.
- *
- *  @note
- *      This base class can be used to pass pointers to the ObjectPoolDynamic and sized ObjectPoolStatic classes without requiring
- * the class holding the reference to be templated on pool size.
- */
-template <typename T>
-class ObjectPoolBase
-{
-public:
-    virtual ~ObjectPoolBase()                                                                                           = default;
-    virtual T * TryCreate()                                                                                             = 0;
-    virtual void Reset()                                                                                                = 0;
-    virtual void GetStatistics(chip::System::Stats::count_t & aNumInUse, chip::System::Stats::count_t & aHighWatermark) = 0;
-};
-
 /**
  *  @class ObjectPoolStatic
  *
@@ -227,10 +207,10 @@ class ObjectPoolBase
  *  @tparam     N   a positive integer number of objects of class T to allocate from the arena.
  */
 template <typename T, size_t N>
-class ObjectPoolStatic : public ObjectPoolBase<T>
+class ObjectPoolStatic
 {
 public:
-    T * TryCreate() override
+    T * TryCreate()
     {
         T * lReturn = nullptr;
         (void) static_cast<Object *>(lReturn); /* In C++-11, this would be a static_assert that T inherits Object. */
@@ -273,11 +253,11 @@ class ObjectPoolStatic : public ObjectPoolBase<T>
      * @param[in/out] aNumInUse    The number of objects in use. If aStartIndex is not 0,
      *                             the function adds to the counter without resetting it first.
      */
-    void GetNumObjectsInUse(unsigned int aStartIndex, unsigned int & aNumInUse)
+    void GetNumObjectsInUse(size_t aStartIndex, size_t & aNumInUse)
     {
-        unsigned int count = 0;
+        size_t count = 0;
 
-        for (unsigned int lIndex = aStartIndex; lIndex < N; ++lIndex)
+        for (size_t lIndex = aStartIndex; lIndex < N; ++lIndex)
         {
             T & lObject = reinterpret_cast<T *>(mArena.uMemory)[lIndex];
 
@@ -294,23 +274,23 @@ class ObjectPoolStatic : public ObjectPoolBase<T>
 
         aNumInUse += count;
     }
-    void UpdateHighWatermark(const unsigned int & aCandidate)
+    void UpdateHighWatermark(const size_t & aCandidate)
     {
-        unsigned int lTmp;
+        size_t lTmp;
         while (aCandidate > (lTmp = mHighWatermark))
         {
             SYSTEM_OBJECT_HWM_TEST_HOOK();
             (void) __sync_bool_compare_and_swap(&mHighWatermark, lTmp, aCandidate);
         }
     }
-    volatile unsigned int mHighWatermark;
+    volatile size_t mHighWatermark;
 #endif
 
-    void GetStatistics(chip::System::Stats::count_t & aNumInUse, chip::System::Stats::count_t & aHighWatermark) override
+    void GetStatistics(chip::System::Stats::count_t & aNumInUse, chip::System::Stats::count_t & aHighWatermark)
     {
 #if CHIP_SYSTEM_CONFIG_PROVIDE_STATISTICS
-        unsigned int lNumInUse;
-        unsigned int lHighWatermark;
+        size_t lNumInUse;
+        size_t lHighWatermark;
 
         GetNumObjectsInUse(0, lNumInUse);
         lHighWatermark = mHighWatermark;
@@ -337,7 +317,7 @@ class ObjectPoolStatic : public ObjectPoolBase<T>
     template <typename Function>
     bool ForEachActiveObject(Function && function)
     {
-        for (unsigned int i = 0; i < N; ++i)
+        for (size_t i = 0; i < N; ++i)
         {
             T & lObject = reinterpret_cast<T *>(mArena.uMemory)[i];
 
@@ -349,7 +329,7 @@ class ObjectPoolStatic : public ObjectPoolBase<T>
         }
         return true;
     }
-    void Reset() override
+    void Reset()
     {
         memset(mArena.uMemory, 0, N * sizeof(T));
 #if CHIP_SYSTEM_CONFIG_PROVIDE_STATISTICS
@@ -369,10 +349,10 @@ class ObjectPoolStatic : public ObjectPoolBase<T>
  *  @tparam     T   a subclass of Object to be allocated.
  */
 template <typename T>
-class ObjectPoolDynamic : public ObjectPoolBase<T>
+class ObjectPoolDynamic
 {
 public:
-    T * TryCreate() override
+    T * TryCreate()
     {
 
         T * newNode = new T();
@@ -420,7 +400,7 @@ class ObjectPoolDynamic : public ObjectPoolBase<T>
         }
         return true;
     }
-    void Reset() override
+    void Reset()
     {
         std::lock_guard<std::mutex> lock(mMutex);
         Object * p = mDummyHead.mNext;
@@ -434,7 +414,7 @@ class ObjectPoolDynamic : public ObjectPoolBase<T>
 
         mDummyHead.mNext = nullptr;
     }
-    void GetStatistics(chip::System::Stats::count_t & aNumInUse, chip::System::Stats::count_t & aHighWatermark) override {}
+    void GetStatistics(chip::System::Stats::count_t & aNumInUse, chip::System::Stats::count_t & aHighWatermark) {}
     std::mutex mMutex;
     Object mDummyHead;
     friend class TestObject;