Do not use ConvertToBaseCallback needlessly in AudioDestination ctor

This method is needed when convert a CrossThreadFunction [1] to pass
it out of Blink. In this particular case, AudioDestination can pass
a CrossThreadFunction instance to blink::MediaMultiChannelResampler
without converting it back to base::RepeatingCallback.

BUG=None

R=jbroman@chromium.org

[1] third_party/blink/renderer/platform/wtf/functional.h

Change-Id: Ifc5d19049dd3e4b295dd6e88d72d2d5d99ee49b3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1599712
Commit-Queue: Antonio Gomes <tonikitoo@igalia.com>
Commit-Queue: Jeremy Roman <jbroman@chromium.org>
Auto-Submit: Antonio Gomes <tonikitoo@igalia.com>
Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#657363}

third_party/blink/renderer/platform/audio/audio_destination.cc

@@ -109,9 +109,9 @@ AudioDestination::AudioDestination(AudioIOCallback& callback,
 
     resampler_.reset(new MediaMultiChannelResampler(
         MaxChannelCount(), scale_factor, audio_utilities::kRenderQuantumFrames,
-        ConvertToBaseCallback(
-            CrossThreadBind(&AudioDestination::ProvideResamplerInput,
-                            CrossThreadUnretained(this)))));
+
+        CrossThreadBind(&AudioDestination::ProvideResamplerInput,
+                        CrossThreadUnretained(this))));
     resampler_bus_ =
         media::AudioBus::CreateWrapper(render_bus_->NumberOfChannels());
     for (unsigned int i = 0; i < render_bus_->NumberOfChannels(); ++i) {

third_party/blink/renderer/platform/audio/media_multi_channel_resampler.cc

@@ -15,8 +15,8 @@ MediaMultiChannelResampler::MediaMultiChannelResampler(
     int channels,
     double io_sample_rate_ratio,
     size_t request_frames,
-    const ReadCB& read_cb)
-    : read_cb_(read_cb) {
+    ReadCB read_cb)
+    : read_cb_(std::move(read_cb)) {
   resampler_.reset(new media::MultiChannelResampler(
       channels, io_sample_rate_ratio, request_frames,
       base::BindRepeating(&MediaMultiChannelResampler::ProvideResamplerInput,

third_party/blink/renderer/platform/audio/media_multi_channel_resampler.h

@@ -11,6 +11,7 @@
 #include "media/base/multi_channel_resampler.h"
 #include "third_party/blink/renderer/platform/platform_export.h"
 #include "third_party/blink/renderer/platform/wtf/allocator.h"
+#include "third_party/blink/renderer/platform/wtf/functional.h"
 
 namespace media {
 class AudioBus;
@@ -29,7 +30,8 @@ class PLATFORM_EXPORT MediaMultiChannelResampler {
   // to be completely filled with data upon return; zero padded if not enough
   // frames are available to satisfy the request.  |frame_delay| is the number
   // of output frames already processed and can be used to estimate delay.
-  typedef base::RepeatingCallback<void(int frame_delay, AudioBus* audio_bus)>
+  typedef WTF::CrossThreadRepeatingFunction<void(int frame_delay,
+                                                 AudioBus* audio_bus)>
       ReadCB;
 
  public:
@@ -40,7 +42,7 @@ class PLATFORM_EXPORT MediaMultiChannelResampler {
   MediaMultiChannelResampler(int channels,
                              double io_sample_rate_ratio,
                              size_t request_frames,
-                             const ReadCB& read_cb);
+                             ReadCB read_cb);
 
   // Resamples |frames| of data from |read_cb_| into AudioBus.
   void Resample(int frames, media::AudioBus* audio_bus);