Logging to investigate a crash

Bug: 6490974
Change-Id: Ib926a9258bde4ee05ed42eea662dff68e426a997
diff --git a/include/media/AudioBufferProvider.h b/include/media/AudioBufferProvider.h
index 43e4de7..865ed7e 100644
--- a/include/media/AudioBufferProvider.h
+++ b/include/media/AudioBufferProvider.h
@@ -36,8 +36,11 @@
         size_t frameCount;
     };
 
-    virtual ~AudioBufferProvider() {}
+protected:
+    AudioBufferProvider() : mValid(kValid) { }
+    virtual ~AudioBufferProvider() { mValid = kDead; }
 
+public:
     // value representing an invalid presentation timestamp
     static const int64_t kInvalidPTS = 0x7FFFFFFFFFFFFFFFLL;    // <stdint.h> is too painful
 
@@ -47,6 +50,13 @@
     virtual status_t getNextBuffer(Buffer* buffer, int64_t pts = kInvalidPTS) = 0;
 
     virtual void releaseBuffer(Buffer* buffer) = 0;
+
+    int getValid() const { return mValid; }
+    static const int kValid = 'GOOD';
+    static const int kDead = 'DEAD';
+
+private:
+    int mValid;
 };
 
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