AudioFlinger methods const and inline

This saves 1063 bytes and probably improves performance.

Change-Id: I11cf0dfd925fbaec75e3d1b806852a538eae5518
diff --git a/services/audioflinger/AudioResampler.h b/services/audioflinger/AudioResampler.h
index ffa690a..b86cdc1 100644
--- a/services/audioflinger/AudioResampler.h
+++ b/services/audioflinger/AudioResampler.h
@@ -54,7 +54,7 @@
             AudioBufferProvider* provider) = 0;
 
     virtual void reset();
-    virtual size_t getUnreleasedFrames() { return mInputIndex; }
+    virtual size_t getUnreleasedFrames() const { return mInputIndex; }
 
 protected:
     // number of bits for phase fraction - 30 bits allows nearly 2x downsampling