IMediaSource: add supportReadMultiple().

Bug: 29331573
Change-Id: I7cdff44878bd93671e98fe11c99d17e82410cdcb
diff --git a/include/media/IMediaSource.h b/include/media/IMediaSource.h
index 709f425..524e7aa 100644
--- a/include/media/IMediaSource.h
+++ b/include/media/IMediaSource.h
@@ -114,6 +114,9 @@
     virtual status_t readMultiple(
             Vector<MediaBuffer *> *buffers, uint32_t maxNumBuffers = 1) = 0;
 
+    // Returns true if |readMultiple| is supported, otherwise false.
+    virtual bool supportReadMultiple() = 0;
+
     // Causes this source to suspend pulling data from its upstream source
     // until a subsequent read-with-seek. Currently only supported by
     // OMXCodec.
@@ -148,6 +151,10 @@
             Vector<MediaBuffer *> * /* buffers */, uint32_t /* maxNumBuffers = 1 */) {
         return ERROR_UNSUPPORTED;
     }
+
+    virtual bool supportReadMultiple() {
+        return false;
+    }
 protected:
     virtual ~BnMediaSource();