Fix skipping to keyframe to use correct position

Issue: #2575

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=150622487

library/core/src/main/java/com/google/android/exoplayer2/BaseRenderer.java

@@ -311,7 +311,7 @@ public abstract class BaseRenderer implements Renderer, RendererCapabilities {
    * @param timeUs The specified time.
    * @param timeUs The specified time.
    */
    */
   protected void skipToKeyframeBefore(long timeUs) {
   protected void skipToKeyframeBefore(long timeUs) {
-    stream.skipToKeyframeBefore(timeUs);
+    stream.skipToKeyframeBefore(timeUs - streamOffsetUs);
   }
   }
 
 
 }
 }