Bug 1034444 - Fix libstagefright warnings; r=cpearce

media/libstagefright/frameworks/av/include/media/stagefright/MediaExtractor.h

@@ -23,7 +23,7 @@
 namespace stagefright {
 
 class DataSource;
-class MediaSource;
+struct MediaSource;
 class MetaData;
 
 class MediaExtractor : public RefBase {

media/libstagefright/frameworks/av/include/media/stagefright/Utils.h

@@ -41,7 +41,7 @@ uint64_t U64LE_AT(const uint8_t *ptr);
 uint64_t ntoh64(uint64_t x);
 uint64_t hton64(uint64_t x);
 
-struct MetaData;
+class MetaData;
 struct AMessage;
 status_t convertMetaDataToMessage(
         const sp<MetaData> &meta, sp<AMessage> *format);

media/libstagefright/frameworks/av/media/libstagefright/include/ID3.h

@@ -22,8 +22,8 @@
 
 namespace stagefright {
 
-struct DataSource;
+class DataSource;
-struct String8;
+class String8;
 
 struct ID3 {
     enum Version {

media/libstagefright/frameworks/av/media/libstagefright/include/SampleIterator.h

@@ -21,7 +21,7 @@
 
 namespace stagefright {
 
-struct SampleTable;
+class SampleTable;
 
 struct SampleIterator {
     SampleIterator(SampleTable *table);