codec2: change of asC2Buffer behavior

Bug: 152617675
Test: atest CtsMediaTestCases:MediaCodecBlockModelTest
Change-Id: Ie5893313840c6f1c349affca15f105520d7965cb
diff --git a/media/codec2/sfplugin/Codec2Buffer.cpp b/media/codec2/sfplugin/Codec2Buffer.cpp
index b6d18e2..5b3a62f 100644
--- a/media/codec2/sfplugin/Codec2Buffer.cpp
+++ b/media/codec2/sfplugin/Codec2Buffer.cpp
@@ -111,7 +111,11 @@
 }
 
 std::shared_ptr<C2Buffer> DummyContainerBuffer::asC2Buffer() {
-    return std::move(mBufferRef);
+    return mBufferRef;
+}
+
+void DummyContainerBuffer::clearC2BufferRefs() {
+    mBufferRef.reset();
 }
 
 bool DummyContainerBuffer::canCopy(const std::shared_ptr<C2Buffer> &) const {
@@ -187,7 +191,11 @@
 }
 
 std::shared_ptr<C2Buffer> ConstLinearBlockBuffer::asC2Buffer() {
-    return std::move(mBufferRef);
+    return mBufferRef;
+}
+
+void ConstLinearBlockBuffer::clearC2BufferRefs() {
+    mBufferRef.reset();
 }
 
 // GraphicView2MediaImageConverter
@@ -689,8 +697,12 @@
 }
 
 std::shared_ptr<C2Buffer> ConstGraphicBlockBuffer::asC2Buffer() {
+    return mBufferRef;
+}
+
+void ConstGraphicBlockBuffer::clearC2BufferRefs() {
     mView.reset();
-    return std::move(mBufferRef);
+    mBufferRef.reset();
 }
 
 bool ConstGraphicBlockBuffer::canCopy(const std::shared_ptr<C2Buffer> &buffer) const {