native: Rename mBuf to mSlot

Remove the union in BufferItem.

Bug: 19769719
Change-Id: I4e496b5aafce0fc5206dc7551a741f9c262c2cd0
diff --git a/libs/gui/CpuConsumer.cpp b/libs/gui/CpuConsumer.cpp
index e29b740..7ed3d0f 100644
--- a/libs/gui/CpuConsumer.cpp
+++ b/libs/gui/CpuConsumer.cpp
@@ -106,22 +106,22 @@
         }
     }
 
-    int buf = b.mBuf;
+    int slot = b.mSlot;
 
     void *bufferPointer = NULL;
     android_ycbcr ycbcr = android_ycbcr();
 
-    PixelFormat format = mSlots[buf].mGraphicBuffer->getPixelFormat();
+    PixelFormat format = mSlots[slot].mGraphicBuffer->getPixelFormat();
     PixelFormat flexFormat = format;
     if (isPossiblyYUV(format)) {
         if (b.mFence.get()) {
-            err = mSlots[buf].mGraphicBuffer->lockAsyncYCbCr(
+            err = mSlots[slot].mGraphicBuffer->lockAsyncYCbCr(
                 GraphicBuffer::USAGE_SW_READ_OFTEN,
                 b.mCrop,
                 &ycbcr,
                 b.mFence->dup());
         } else {
-            err = mSlots[buf].mGraphicBuffer->lockYCbCr(
+            err = mSlots[slot].mGraphicBuffer->lockYCbCr(
                 GraphicBuffer::USAGE_SW_READ_OFTEN,
                 b.mCrop,
                 &ycbcr);
@@ -141,13 +141,13 @@
 
     if (bufferPointer == NULL) { // not flexible YUV
         if (b.mFence.get()) {
-            err = mSlots[buf].mGraphicBuffer->lockAsync(
+            err = mSlots[slot].mGraphicBuffer->lockAsync(
                 GraphicBuffer::USAGE_SW_READ_OFTEN,
                 b.mCrop,
                 &bufferPointer,
                 b.mFence->dup());
         } else {
-            err = mSlots[buf].mGraphicBuffer->lock(
+            err = mSlots[slot].mGraphicBuffer->lock(
                 GraphicBuffer::USAGE_SW_READ_OFTEN,
                 b.mCrop,
                 &bufferPointer);
@@ -169,19 +169,19 @@
     assert(lockedIdx < mMaxLockedBuffers);
 
     AcquiredBuffer &ab = mAcquiredBuffers.editItemAt(lockedIdx);
-    ab.mSlot = buf;
+    ab.mSlot = slot;
     ab.mBufferPointer = bufferPointer;
-    ab.mGraphicBuffer = mSlots[buf].mGraphicBuffer;
+    ab.mGraphicBuffer = mSlots[slot].mGraphicBuffer;
 
     nativeBuffer->data   =
             reinterpret_cast<uint8_t*>(bufferPointer);
-    nativeBuffer->width  = mSlots[buf].mGraphicBuffer->getWidth();
-    nativeBuffer->height = mSlots[buf].mGraphicBuffer->getHeight();
+    nativeBuffer->width  = mSlots[slot].mGraphicBuffer->getWidth();
+    nativeBuffer->height = mSlots[slot].mGraphicBuffer->getHeight();
     nativeBuffer->format = format;
     nativeBuffer->flexFormat = flexFormat;
     nativeBuffer->stride = (ycbcr.y != NULL) ?
             static_cast<uint32_t>(ycbcr.ystride) :
-            mSlots[buf].mGraphicBuffer->getStride();
+            mSlots[slot].mGraphicBuffer->getStride();
 
     nativeBuffer->crop        = b.mCrop;
     nativeBuffer->transform   = b.mTransform;