libgui: Remove RefBase from BitTube

Removes RefBase from BitTube, since because it is not a Binder object,
it doesn't need to be reference-counted in this way.

In the process, we rename IDisplayEventConnection::getDataChannel to
IDEC::stealReceiveChannel to make it clearer that this is a non-const
operation on the remote end that removes its access to the receive
channel.

This also adds a couple of methods for moving the receive file
descriptor out of one BitTube and into another, since this is the
essence of the IDisplayEventConnection::stealReceiveChannel method,
and now with C++11 move semantics, we can do this without needing to
return an sp<> from EventThread's implementation of stealReceiveChannel.

Test: m -j + manual testing
Change-Id: Ibaaca2a14fb6155052fe5434c14bc3e671b43743

1 files changed, 5 insertions, 4 deletions

diff --git a/libs/gui/DisplayEventReceiver.cpp b/libs/gui/DisplayEventReceiver.cpp
index a3ae68c565..1507d51fca 100644
--- a/libs/gui/DisplayEventReceiver.cpp
+++ b/libs/gui/DisplayEventReceiver.cpp
@@ -37,7 +37,8 @@ DisplayEventReceiver::DisplayEventReceiver() {
     if (sf != NULL) {
         mEventConnection = sf->createDisplayEventConnection();
         if (mEventConnection != NULL) {
-            mEventConnection->getDataChannel(&mDataChannel);
+            mDataChannel = std::make_unique<gui::BitTube>();
+            mEventConnection->stealReceiveChannel(mDataChannel.get());
         }
     }
 }
@@ -80,16 +81,16 @@ status_t DisplayEventReceiver::requestNextVsync() {
 
 ssize_t DisplayEventReceiver::getEvents(DisplayEventReceiver::Event* events,
         size_t count) {
-    return DisplayEventReceiver::getEvents(mDataChannel, events, count);
+    return DisplayEventReceiver::getEvents(mDataChannel.get(), events, count);
 }
 
-ssize_t DisplayEventReceiver::getEvents(const sp<gui::BitTube>& dataChannel,
+ssize_t DisplayEventReceiver::getEvents(gui::BitTube* dataChannel,
         Event* events, size_t count)
 {
     return gui::BitTube::recvObjects(dataChannel, events, count);
 }
 
-ssize_t DisplayEventReceiver::sendEvents(const sp<gui::BitTube>& dataChannel,
+ssize_t DisplayEventReceiver::sendEvents(gui::BitTube* dataChannel,
         Event const* events, size_t count)
 {
     return gui::BitTube::sendObjects(dataChannel, events, count);