Start cleaning up 64bit Win warnings

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
@@ skipping 23 matching lines @@
     SkASSERT(fHead == fTail);
     SkASSERT(0 == fHead->fLiveCount);
     DeleteBlock(fHead);
 };
 
 void* GrMemoryPool::allocate(size_t size) {
     VALIDATE;
     size = GrSizeAlignUp(size, kAlignment);
     size += kPerAllocPad;
     if (fTail->fFreeSize < size) {
-        int blockSize = size;
+        size_t blockSize = size;
         blockSize = GrMax<size_t>(blockSize, fMinAllocSize);
         BlockHeader* block = CreateBlock(blockSize);
 
         block->fPrev = fTail;
         block->fNext = NULL;
         SkASSERT(NULL == fTail->fNext);
         fTail->fNext = block;
         fTail = block;
     }
     SkASSERT(fTail->fFreeSize >= size);
@@ skipping 97 matching lines @@
             SkASSERT(userStart == block->fCurrPtr);
         } else {
             SkASSERT(block == *reinterpret_cast<BlockHeader**>(userStart));
         }
         prev = block;
     } while ((block = block->fNext));
     SkASSERT(allocCount == fAllocationCnt);
     SkASSERT(prev == fTail);
 #endif
 }