libmediaplayerservice: fix warnings, make warnings errors, use clang

Change-Id: I1b2f6b65c5abbc366068a60b8909104f31b94228
diff --git a/media/libmediaplayerservice/VideoFrameScheduler.h b/media/libmediaplayerservice/VideoFrameScheduler.h
index 84b27b4..b1765c9 100644
--- a/media/libmediaplayerservice/VideoFrameScheduler.h
+++ b/media/libmediaplayerservice/VideoFrameScheduler.h
@@ -24,7 +24,7 @@
 
 namespace android {
 
-struct ISurfaceComposer;
+class ISurfaceComposer;
 
 struct VideoFrameScheduler : public RefBase {
     VideoFrameScheduler();