libgui/SurfaceFlinger: Add getConsumerName

Adds a getConsumerName method to IGraphicBufferProducer and Surface.
Currently, the name is cached inside of IGBP and is update on connect
and dequeueBuffer, which should be good enough for most uses.

Bug: 6667401
Change-Id: I22c7881d778e495cf8276de7bbcd769e52429915
diff --git a/services/surfaceflinger/MonitoredProducer.h b/services/surfaceflinger/MonitoredProducer.h
index ff691d8..da95766 100644
--- a/services/surfaceflinger/MonitoredProducer.h
+++ b/services/surfaceflinger/MonitoredProducer.h
@@ -55,6 +55,7 @@
             PixelFormat format, uint32_t usage);
     virtual status_t allowAllocation(bool allow);
     virtual status_t setGenerationNumber(uint32_t generationNumber);
+    virtual String8 getConsumerName() const override;
     virtual IBinder* onAsBinder();
 
 private: