Remove unused output parameter in VCMReceiver::FrameForDecoding().

BUG=
R=pbos@webrtc.org

Review URL: https://codereview.webrtc.org/2104863002 .

Cr-Commit-Position: refs/heads/master@{#13310}
diff --git a/webrtc/modules/video_coding/receiver_unittest.cc b/webrtc/modules/video_coding/receiver_unittest.cc
index 863dac3..b2a3a36 100644
--- a/webrtc/modules/video_coding/receiver_unittest.cc
+++ b/webrtc/modules/video_coding/receiver_unittest.cc
@@ -73,9 +73,7 @@
   }
 
   bool DecodeNextFrame() {
-    int64_t render_time_ms = 0;
-    VCMEncodedFrame* frame =
-        receiver_.FrameForDecoding(0, &render_time_ms, false);
+    VCMEncodedFrame* frame = receiver_.FrameForDecoding(0, false);
     if (!frame)
       return false;
     receiver_.ReleaseFrame(frame);
@@ -409,7 +407,6 @@
   const int kFramePeriod = 40;
   int64_t arrive_timestamps[kNumFrames];
   int64_t render_timestamps[kNumFrames];
-  int64_t next_render_time;
 
   // Construct test samples.
   // render_timestamps are the timestamps stored in the Frame;
@@ -435,8 +432,7 @@
   // build bot to kill the test.
   while (num_frames_return < kNumFrames) {
     int64_t start_time = clock_.TimeInMilliseconds();
-    VCMEncodedFrame* frame =
-        receiver_.FrameForDecoding(kMaxWaitTime, &next_render_time, false);
+    VCMEncodedFrame* frame = receiver_.FrameForDecoding(kMaxWaitTime, false);
     int64_t end_time = clock_.TimeInMilliseconds();
 
     // In any case the FrameForDecoding should not wait longer than
@@ -467,7 +463,6 @@
 
   int64_t arrive_timestamps[kNumFrames];
   int64_t render_timestamps[kNumFrames];
-  int64_t next_render_time;
 
   int render_delay_ms;
   int max_decode_ms;
@@ -496,8 +491,8 @@
   while (num_frames_return < kNumFrames) {
     int64_t start_time = clock_.TimeInMilliseconds();
 
-    VCMEncodedFrame* frame = receiver_.FrameForDecoding(
-        kMaxWaitTime, &next_render_time, prefer_late_decoding);
+    VCMEncodedFrame* frame =
+        receiver_.FrameForDecoding(kMaxWaitTime, prefer_late_decoding);
     int64_t end_time = clock_.TimeInMilliseconds();
     if (frame) {
       EXPECT_EQ(frame->RenderTimeMs() - max_decode_ms - render_delay_ms,