mediaplayer: add buffering settings API

Test: compiles, checked that params is passed all the way to source.
Bug:32524218
Change-Id: I637d1ab09f94a3830a33a39e7e9f1b3efb22357f
diff --git a/media/libmedia/BufferingSettings.cpp b/media/libmedia/BufferingSettings.cpp
index 5d6e03d..a69497e 100644
--- a/media/libmedia/BufferingSettings.cpp
+++ b/media/libmedia/BufferingSettings.cpp
@@ -80,4 +80,15 @@
     return OK;
 }
 
+String8 BufferingSettings::toString() const {
+    String8 s;
+    s.appendFormat("initialMode(%d), rebufferingMode(%d), "
+            "initialMarks(%d ms, %d KB), rebufferingMarks(%d, %d)ms, (%d, %d)KB",
+            mInitialBufferingMode, mRebufferingMode,
+            mInitialWatermarkMs, mInitialWatermarkKB,
+            mRebufferingWatermarkLowMs, mRebufferingWatermarkHighMs,
+            mRebufferingWatermarkLowKB, mRebufferingWatermarkHighKB);
+    return s;
+}
+
 } // namespace android