remoting::WebrtcVideoEncoderGpu shared memory refactor

This CL changes usages of deprecated base::SharedMemory to
base::UnsafeSharedMemoryRegion. No functional changes.

Bug: 795291
Change-Id: I6d58ab32cb054760abaf5554e96d634569b69ccd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1919339Reviewed-by: Gary Kacmarcik <garykac@chromium.org>
Commit-Queue: Alex Ilin <alexilin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#715788}

remoting/codec/webrtc_video_encoder_gpu.cc

@@ -157,10 +157,13 @@ void WebrtcVideoEncoderGpu::RequireBitstreamBuffers(
   output_buffers_.clear();
 
   for (unsigned int i = 0; i < kWebrtcVideoEncoderGpuOutputBufferCount; ++i) {
-    auto shm = std::make_unique<base::SharedMemory>();
+    auto output_buffer = std::make_unique<OutputBuffer>();
+    output_buffer->region =
+        base::UnsafeSharedMemoryRegion::Create(output_buffer_size_);
+    output_buffer->mapping = output_buffer->region.Map();
     // TODO(gusss): Do we need to handle mapping failure more gracefully?
-    CHECK(shm->CreateAndMapAnonymous(output_buffer_size_));
-    output_buffers_.push_back(std::move(shm));
+    CHECK(output_buffer->IsValid());
+    output_buffers_.push_back(std::move(output_buffer));
   }
 
   for (size_t i = 0; i < output_buffers_.size(); ++i) {
@@ -182,11 +185,11 @@ void WebrtcVideoEncoderGpu::BitstreamBufferReady(
 
   std::unique_ptr<EncodedFrame> encoded_frame =
       std::make_unique<EncodedFrame>();
-  base::SharedMemory* output_buffer =
-      output_buffers_[bitstream_buffer_id].get();
-  DCHECK(output_buffer->memory());
-  encoded_frame->data.assign(reinterpret_cast<char*>(output_buffer->memory()),
-                             metadata.payload_size_bytes);
+  OutputBuffer* output_buffer = output_buffers_[bitstream_buffer_id].get();
+  DCHECK(output_buffer->IsValid());
+  base::span<char> data_span =
+      output_buffer->mapping.GetMemoryAsSpan<char>(metadata.payload_size_bytes);
+  encoded_frame->data.assign(data_span.begin(), data_span.end());
   encoded_frame->key_frame = metadata.key_frame;
   encoded_frame->size = webrtc::DesktopSize(input_coded_size_.width(),
                                             input_coded_size_.height());
@@ -208,6 +211,10 @@ void WebrtcVideoEncoderGpu::NotifyError(
   LOG(ERROR) << __func__ << " error: " << error;
 }
 
+bool WebrtcVideoEncoderGpu::OutputBuffer::IsValid() {
+  return region.IsValid() && mapping.IsValid();
+}
+
 void WebrtcVideoEncoderGpu::BeginInitialization() {
   DVLOG(3) << __func__;
 
@@ -238,8 +245,9 @@ void WebrtcVideoEncoderGpu::UseOutputBitstreamBufferId(
     int32_t bitstream_buffer_id) {
   DVLOG(3) << __func__ << " id=" << bitstream_buffer_id;
   video_encode_accelerator_->UseOutputBitstreamBuffer(media::BitstreamBuffer(
-      bitstream_buffer_id, output_buffers_[bitstream_buffer_id]->handle(),
-      false /* read_only */, output_buffer_size_));
+      bitstream_buffer_id,
+      output_buffers_[bitstream_buffer_id]->region.Duplicate(),
+      output_buffers_[bitstream_buffer_id]->region.GetSize()));
 }
 
 void WebrtcVideoEncoderGpu::RunAnyPendingEncode() {

remoting/codec/webrtc_video_encoder_gpu.h

@@ -5,15 +5,13 @@
 #ifndef REMOTING_CODEC_WEBRTC_VIDEO_ENCODER_GPU_H_
 #define REMOTING_CODEC_WEBRTC_VIDEO_ENCODER_GPU_H_
 
+#include "base/memory/shared_memory_mapping.h"
+#include "base/memory/unsafe_shared_memory_region.h"
 #include "media/video/video_encode_accelerator.h"
 #include "remoting/codec/encoder_bitrate_filter.h"
 #include "remoting/codec/webrtc_video_encoder.h"
 #include "remoting/codec/webrtc_video_encoder_selector.h"
 
-namespace base {
-class SharedMemory;
-}
-
 namespace remoting {
 
 // A WebrtcVideoEncoder implementation utilizing the VideoEncodeAccelerator
@@ -59,6 +57,13 @@ class WebrtcVideoEncoderGpu : public WebrtcVideoEncoder,
  private:
   enum State { UNINITIALIZED, INITIALIZING, INITIALIZED, INITIALIZATION_ERROR };
 
+  struct OutputBuffer {
+    base::UnsafeSharedMemoryRegion region;
+    base::WritableSharedMemoryMapping mapping;
+
+    bool IsValid();
+  };
+
   explicit WebrtcVideoEncoderGpu(media::VideoCodecProfile codec_profile);
 
   void BeginInitialization();
@@ -81,7 +86,7 @@ class WebrtcVideoEncoderGpu : public WebrtcVideoEncoder,
   media::VideoCodecProfile codec_profile_;
 
   // Shared memory with which the VEA transfers output to WebrtcVideoEncoderGpu
-  std::vector<std::unique_ptr<base::SharedMemory>> output_buffers_;
+  std::vector<std::unique_ptr<OutputBuffer>> output_buffers_;
 
   // TODO(gusss): required_input_frame_count_ is currently unused; evaluate
   // whether or not it's actually needed. This variable represents the number of