Return 'correct' size from GrMemoryPool

src/gpu/GrMemoryPool.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrMemoryPool.h"
 
 #ifdef SK_DEBUG
     #define VALIDATE this->validate()
 #else
     #define VALIDATE
 #endif
 
 GrMemoryPool::GrMemoryPool(size_t preallocSize, size_t minAllocSize) {
     SkDEBUGCODE(fAllocationCnt = 0);
     SkDEBUGCODE(fAllocBlockCnt = 0);
 
     minAllocSize = SkTMax<size_t>(minAllocSize, 1 << 10);
     fMinAllocSize = GrSizeAlignUp(minAllocSize + kPerAllocPad, kAlignment),
     fPreallocSize = GrSizeAlignUp(preallocSize + kPerAllocPad, kAlignment);
     fPreallocSize = SkTMax(fPreallocSize, fMinAllocSize);
-    fSize = fPreallocSize;
+    fSize = 0;
 
     fHead = CreateBlock(fPreallocSize);
     fTail = fHead;
     fHead->fNext = nullptr;
     fHead->fPrev = nullptr;
     VALIDATE;
 };
 
 GrMemoryPool::~GrMemoryPool() {
     VALIDATE;
@@ skipping 123 matching lines @@
         if (!block->fLiveCount) {
             SkASSERT(ptrOffset ==  kHeaderSize);
             SkASSERT(userStart == block->fCurrPtr);
         } else {
             SkASSERT(block == *reinterpret_cast<BlockHeader**>(userStart));
         }
         prev = block;
     } while ((block = block->fNext));
     SkASSERT(allocCount == fAllocationCnt);
     SkASSERT(prev == fTail);
-    SkASSERT(fAllocBlockCnt != 0 || fSize == fPreallocSize);
+    SkASSERT(fAllocBlockCnt != 0 || fSize == 0);
 #endif
 }