Revert of Add EncodedImageCallback::OnEncodedImage(). (patchset #13 id:280001 of https://codereview.webrtc.org/2089773002/ )

Reason for revert:
broke internal tests

Original issue's description:
> Add EncodedImageCallback::OnEncodedImage().
>
> OnEncodedImage() is going to replace Encoded(), which is deprecated now.
> The new OnEncodedImage() returns Result struct that contains frame_id,
> which tells the encoder RTP timestamp for the frame.
>
> BUG=chromium:621691
> R=niklas.enbom@webrtc.org, sprang@webrtc.org, stefan@webrtc.org
>
> Committed: https://crrev.com/ad34dbe934d47f88011045671b4aea00dbd5a795
> Cr-Commit-Position: refs/heads/master@{#13613}

TBR=pbos@webrtc.org,mflodman@webrtc.org,sprang@webrtc.org,stefan@webrtc.org,niklas.enbom@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:621691

Review-Url: https://codereview.webrtc.org/2206743002
Cr-Commit-Position: refs/heads/master@{#13614}
diff --git a/webrtc/modules/video_coding/generic_encoder.cc b/webrtc/modules/video_coding/generic_encoder.cc
index 28eb10a..e63da02 100644
--- a/webrtc/modules/video_coding/generic_encoder.cc
+++ b/webrtc/modules/video_coding/generic_encoder.cc
@@ -21,7 +21,6 @@
 #include "webrtc/system_wrappers/include/critical_section_wrapper.h"
 
 namespace webrtc {
-
 VCMGenericEncoder::VCMGenericEncoder(
     VideoEncoder* encoder,
     VCMEncodedFrameCallback* encoded_frame_callback,
@@ -144,25 +143,23 @@
 
 VCMEncodedFrameCallback::~VCMEncodedFrameCallback() {}
 
-EncodedImageCallback::Result VCMEncodedFrameCallback::OnEncodedImage(
+int32_t VCMEncodedFrameCallback::Encoded(
     const EncodedImage& encoded_image,
     const CodecSpecificInfo* codec_specific,
     const RTPFragmentationHeader* fragmentation_header) {
   TRACE_EVENT_INSTANT1("webrtc", "VCMEncodedFrameCallback::Encoded",
                        "timestamp", encoded_image._timeStamp);
-  Result result = post_encode_callback_->OnEncodedImage(
-      encoded_image, codec_specific, fragmentation_header);
-  if (result.error != Result::OK)
-    return result;
+  int ret_val = post_encode_callback_->Encoded(encoded_image, codec_specific,
+                                               fragmentation_header);
+  if (ret_val < 0)
+    return ret_val;
 
   if (media_opt_) {
     media_opt_->UpdateWithEncodedData(encoded_image);
-    if (internal_source_) {
-      // Signal to encoder to drop next frame.
-      result.drop_next_frame = media_opt_->DropFrame();
-    }
+    if (internal_source_)
+      return media_opt_->DropFrame();  // Signal to encoder to drop next frame.
   }
-  return result;
+  return VCM_OK;
 }
 
 }  // namespace webrtc