libmediaplayerservice: fix warnings, make warnings errors, use clang

namespace android {

struct AMessage;

struct Parcel;

class Parcel;

struct CodecCapabilities;

typedef KeyedVector<AString, AString> CodecSettings;

namespace android {

class ALooper;

struct ALooper;

class AMessage;

struct AReplyToken;

class IGraphicBufferProducer;

struct ABuffer;

struct AHandler;

struct AString;

struct Parcel;

class Parcel;

struct AReplyToken : public RefBase {

    AReplyToken(const sp<ALooper> &looper)

namespace android {

class String8;

struct Parcel;

class Parcel;

struct AString {

    AString();

namespace android {

class ALooper;

struct ALooper;

struct IMediaHTTPService;

class MediaPlayerBase;

class MediaSource;