CCodec: FrameReassembler to accept 0-size frames

0-sized EOS frame is used to signal EOS and drain the data.

Bug: 193885332
Test: atest ccodec_unit_test
Change-Id: Iabd262d1c68e0f29ce8019f57967de1ad6009c77
diff --git a/media/codec2/sfplugin/CCodecBufferChannel.cpp b/media/codec2/sfplugin/CCodecBufferChannel.cpp
index 2dc63f3..00dd0e5 100644
--- a/media/codec2/sfplugin/CCodecBufferChannel.cpp
+++ b/media/codec2/sfplugin/CCodecBufferChannel.cpp
@@ -276,6 +276,12 @@
             }
         }
     } else if (eos) {
+        Mutexed<Input>::Locked input(mInput);
+        if (input->frameReassembler) {
+            usesFrameReassembler = true;
+            // drain any pending items with eos
+            input->frameReassembler.process(buffer, &items);
+        }
         flags |= C2FrameData::FLAG_END_OF_STREAM;
     }
     if (usesFrameReassembler) {