Enable write side of MonoPipe to be shutdown

Bug: 7253033
Change-Id: Iea8390763b59ffa7a8e2a6b77dd04ea23442698f
diff --git a/media/libnbaio/MonoPipe.cpp b/media/libnbaio/MonoPipe.cpp
index bbdc8c1..e8d3d9b 100644
--- a/media/libnbaio/MonoPipe.cpp
+++ b/media/libnbaio/MonoPipe.cpp
@@ -41,7 +41,8 @@
         mWriteTsValid(false),
         // mWriteTs
         mSetpoint((reqFrames * 11) / 16),
-        mWriteCanBlock(writeCanBlock)
+        mWriteCanBlock(writeCanBlock),
+        mIsShutdown(false)
 {
     CCHelper tmpHelper;
     status_t res;
@@ -121,7 +122,7 @@
             android_atomic_release_store(written + mRear, &mRear);
             totalFramesWritten += written;
         }
-        if (!mWriteCanBlock) {
+        if (!mWriteCanBlock || mIsShutdown) {
             break;
         }
         count -= written;
@@ -299,4 +300,14 @@
     return ts + frame_lt_duration;
 }
 
+void MonoPipe::shutdown(bool newState)
+{
+    mIsShutdown = newState;
+}
+
+bool MonoPipe::isShutdown()
+{
+    return mIsShutdown;
+}
+
 }   // namespace android