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/include/gui/Surface.h b/include/gui/Surface.h
index 261b07c..72f1067 100644
--- a/include/gui/Surface.h
+++ b/include/gui/Surface.h
@@ -106,6 +106,9 @@
      * See IGBP::setGenerationNumber for more information. */
     status_t setGenerationNumber(uint32_t generationNumber);
 
+    // See IGraphicBufferProducer::getConsumerName
+    String8 getConsumerName() const;
+
 protected:
     virtual ~Surface();