Expose IGBP getter

Useful for comparing a SurfaceControl to an existing Surface,
but without calling getSurface which may cause the allocation of
an as of yet unexisting Surface wrapper.

Bug: 122588130
Test: None
Change-Id: I5742bf6af06bd48013a2418b583de8eeeecba2df
diff --git a/libs/gui/SurfaceControl.cpp b/libs/gui/SurfaceControl.cpp
index 8e500a4..008f520 100644
--- a/libs/gui/SurfaceControl.cpp
+++ b/libs/gui/SurfaceControl.cpp
@@ -177,6 +177,12 @@
     return mHandle;
 }
 
+sp<IGraphicBufferProducer> SurfaceControl::getIGraphicBufferProducer() const
+{
+    Mutex::Autolock _l(mLock);
+    return mGraphicBufferProducer;
+}
+
 sp<SurfaceComposerClient> SurfaceControl::getClient() const
 {
     return mClient;