Adding 64 bit checks

src/core/SkScaledImageCache.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkScaledImageCache.h"
 #include "SkMipMap.h"
 #include "SkPixelRef.h"
@@ skipping 248 matching lines @@
 
     virtual bool allocPixelRef(SkBitmap*, SkColorTable*) SK_OVERRIDE;
 
 private:
     SkScaledImageCache::DiscardableFactory fFactory;
 };
 
 bool SkScaledImageCacheDiscardableAllocator::allocPixelRef(SkBitmap* bitmap,
                                                        SkColorTable* ctable) {
     size_t size = bitmap->getSize();
-    if (0 == size) {
+    uint64_t size64 = bitmap->computeSize64();
+    if (0 == size || size64 > (uint64_t)size) {
         return false;
     }
 
     SkDiscardableMemory* dm = fFactory(size);
     if (NULL == dm) {
         return false;
     }
 
     // can we relax this?
     if (kN32_SkColorType != bitmap->colorType()) {
@@ skipping 503 matching lines @@
     return SkScaledImageCache::GetBytesUsed();
 }
 
 size_t SkGraphics::GetImageCacheByteLimit() {
     return SkScaledImageCache::GetByteLimit();
 }
 
 size_t SkGraphics::SetImageCacheByteLimit(size_t newLimit) {
     return SkScaledImageCache::SetByteLimit(newLimit);
 }