GraphicBuffer是surface的内存数据载体，
但是，在Surface::lock方法获取内存信息时，
//frameworks/native/libs/gui/Surface.cpp
status_t Surface::lock(ANativeWindow_Buffer* outBuffer, ARect* inOutDirtyBounds)
{......ANativeWindowBuffer* out;int fenceFd = -1;//拿到一个缓冲区status_t err = dequeueBuffer(&out, &fenceFd);if (err == NO_ERROR) {sp<GraphicBuffer> backBuffer(GraphicBuffer::getSelf(out));......void* vaddr;status_t res = backBuffer->lockAsync(GRALLOC_USAGE_SW_READ_OFTEN | GRALLOC_USAGE_SW_WRITE_OFTEN,newDirtyRegion.bounds(), &vaddr, fenceFd);if (res != 0) {err = INVALID_OPERATION;} else {mLockedBuffer = backBuffer;outBuffer->width = backBuffer->width;outBuffer->height = backBuffer->height;outBuffer->stride = backBuffer->stride;outBuffer->format = backBuffer->format;outBuffer->bits = vaddr;}}return err;
}看上去dequeueBuffer调用把数据保存到了ANativeWindowBuffer中，再通过GraphicBuffer的getSelf处理进行了转换，
ANativeWindowBuffer* out;int fenceFd = -1;//拿到一个缓冲区status_t err = dequeueBuffer(&out, &fenceFd);if (err == NO_ERROR) {sp<GraphicBuffer> backBuffer(GraphicBuffer::getSelf(out));GraphicBuffer 和 ANativeWindowBuffer是什么关系呢，稍微看一下定义，就可以发现，可以把他们理解为一个东西，
frameworks/native/include/ui/GraphicBuffer.h
44class GraphicBuffer 45 : public ANativeObjectBase<ANativeWindowBuffer, GraphicBuffer, RefBase>, 46 public Flattenable<GraphicBuffer>
在其父类ANativeObjectBase中，可以看到
33/* 34 * This helper class turns a ANativeXXX object type into a C++ 35 * reference-counted object; with proper type conversions. 36 */ 37template <typename NATIVE_TYPE, typename TYPE, typename REF, 38 typename NATIVE_BASE = android_native_base_t> 39class ANativeObjectBase : public NATIVE_TYPE, public REF 40{
56 static inline TYPE* getSelf(NATIVE_TYPE* self) { 57 return static_cast<TYPE*>(self); 58 }
只是一个类型转换
参考资料：
https://zhuanlan.zhihu.com/p/30535788
