IOMX: add API for setPortMode

- Add setPortMode to centralize port mode configuration

- Remove storeMetaDataInBuffers and enableNativeBuffers. These are
  no longer exposed to the client. Metadata mode and native/secure
  buffer mode will be enabled by OMX as needed by the port mode.

- Move handling of legacy adpative experiment (legacy metadata mode)
  to OMX side. Legacy mode will now appear the same as non-metadata
  mode to client.

bug: 31399200

Change-Id: Iaf33bd7c30fab4acbc19e9fb8c19e322f9b4a0a0
diff --git a/include/media/OMXBuffer.h b/include/media/OMXBuffer.h
index 0322b73..89b709c 100644
--- a/include/media/OMXBuffer.h
+++ b/include/media/OMXBuffer.h
@@ -44,7 +44,7 @@
     OMXBuffer(const sp<MediaCodecBuffer> &codecBuffer);
 
     // Constructs a buffer of type kBufferTypeSharedMem.
-    OMXBuffer(const sp<IMemory> &mem, size_t allottedSize = 0);
+    OMXBuffer(const sp<IMemory> &mem);
 
     // Constructs a buffer of type kBufferTypeANWBuffer.
     OMXBuffer(const sp<GraphicBuffer> &gbuf);
@@ -78,7 +78,6 @@
 
     // kBufferTypeSharedMem
     sp<IMemory> mMem;
-    OMX_U32 mAllottedSize;
 
     // kBufferTypeANWBuffer
     sp<GraphicBuffer> mGraphicBuffer;