Enable RTCVideoDecoder SW H264 fallback only when it is available

content/renderer/media/rtc_video_decoder.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/media/rtc_video_decoder.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "base/metrics/histogram.h"
 #include "base/numerics/safe_conversions.h"
 #include "base/stl_util.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/task_runner_util.h"
 #include "content/renderer/media/webrtc/webrtc_video_frame_adapter.h"
 #include "gpu/command_buffer/common/mailbox_holder.h"
 #include "media/base/bind_to_current_loop.h"
 #include "media/renderers/gpu_video_accelerator_factories.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/webrtc/base/bind.h"
 #include "third_party/webrtc/base/refcount.h"
+#include "third_party/webrtc/modules/video_coding/codecs/h264/include/h264.h"
 #include "third_party/webrtc/video_frame.h"
 
 #if defined(OS_WIN)
 #include "base/command_line.h"
 #include "base/win/windows_version.h"
 #include "content/public/common/content_switches.h"
 #endif  // defined(OS_WIN)
 
 namespace content {
 
@@ skipping 138 matching lines @@
   base::AutoLock auto_lock(lock_);
 
   if (state_ == UNINITIALIZED || !decode_complete_callback_) {
     LOG(ERROR) << "The decoder has not initialized.";
     return WEBRTC_VIDEO_CODEC_UNINITIALIZED;
   }
 
   if (state_ == DECODE_ERROR) {
     LOG(ERROR) << "Decoding error occurred.";
     // Try reseting the session up to |kNumVDAErrorsHandled| times.
-    if (vda_error_counter_ > kNumVDAErrorsBeforeSWFallback) {
+    // Check if SW H264 implementation is available before falling back.
+    if (vda_error_counter_ > kNumVDAErrorsBeforeSWFallback &&
+        (video_codec_type_ != webrtc::kVideoCodecH264 ||
+         webrtc::H264Decoder::IsSupported())) {
       DLOG(ERROR) << vda_error_counter_
                   << " errors reported by VDA, falling back to software decode";
       return WEBRTC_VIDEO_CODEC_FALLBACK_SOFTWARE;
     }
     base::AutoUnlock auto_unlock(lock_);
     Release();
     return WEBRTC_VIDEO_CODEC_ERROR;
   }
 
   if (missingFrames || !inputImage._completeFrame) {
@@ skipping 684 matching lines @@
 
 void RTCVideoDecoder::TryResetVDAErrorCounter_Locked() {
   lock_.AssertAcquired();
 
   if (vda_error_counter_ == 0)
     return;
   vda_error_counter_ = 0;
 }
 
 }  // namespace content