Rename ISurfaceTexture and SurfaceTexture

The C++ class names don't match what the classes do, so rename
ISurfaceTexture to IGraphicBufferProducer, and SurfaceTexture to
GLConsumer.

Bug 7736700

Change-Id: Ia03e468888025b5cae3c0ee1995434515dbea387
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index a1d46d9..8c2dade 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -127,8 +127,8 @@
 {
     class BSurface : public BnSurface, public LayerCleaner {
         wp<const Layer> mOwner;
-        virtual sp<ISurfaceTexture> getSurfaceTexture() const {
-            sp<ISurfaceTexture> res;
+        virtual sp<IGraphicBufferProducer> getSurfaceTexture() const {
+            sp<IGraphicBufferProducer> res;
             sp<const Layer> that( mOwner.promote() );
             if (that != NULL) {
                 res = that->mSurfaceFlingerConsumer->getBufferQueue();