Fix glop rendering within unclipped saveLayers

bug:19541881

Additionally, clean up GlopBuilders
and rename onGetSnapshot() for clarity

Change-Id: I0303e4cd61eef87cf80af2d968c4aa67193cd008
diff --git a/libs/hwui/CanvasState.cpp b/libs/hwui/CanvasState.cpp
index 85f860d..e88e9f6 100644
--- a/libs/hwui/CanvasState.cpp
+++ b/libs/hwui/CanvasState.cpp
@@ -43,7 +43,7 @@
     mSnapshot = new Snapshot(mFirstSnapshot,
             SkCanvas::kMatrix_SaveFlag | SkCanvas::kClip_SaveFlag);
     mSnapshot->setClip(clipLeft, clipTop, clipRight, clipBottom);
-    mSnapshot->fbo = mCanvas.onGetTargetFbo();
+    mSnapshot->fbo = mCanvas.getTargetFbo();
     mSnapshot->setRelativeLightCenter(lightCenter);
     mSaveCount = 1;
 }