FakeVideoCaptureDevice: add support for capturing into Dma-Bufs using VGEM in CrOs

content/browser/renderer_host/media/video_capture_buffer_pool.cc

Index: content/browser/renderer_host/media/video_capture_buffer_pool.cc
diff --git a/content/browser/renderer_host/media/video_capture_buffer_pool.cc b/content/browser/renderer_host/media/video_capture_buffer_pool.cc
index 894a6710d0ddfc8e7b91351f7d98b5984d877e0b..14d806482ede23f1ff2a6dae485f9ef076fdc035 100644
--- a/content/browser/renderer_host/media/video_capture_buffer_pool.cc
+++ b/content/browser/renderer_host/media/video_capture_buffer_pool.cc
@@ -41,7 +41,10 @@ VideoFrame::Format VideoPixelFormatToVideoFrameFormat(
 // A simple holder of a memory-backed buffer and accesors to it.
 class SimpleBufferHandle final : public VideoCaptureBufferPool::BufferHandle {
  public:
-  SimpleBufferHandle(void* data, size_t size) : data_(data), size_(size) {}
+  SimpleBufferHandle(const base::SharedMemory& shared_memory)
+      : shared_memory_(shared_memory),
+        data_(shared_memory.memory()),
+        size_(shared_memory.mapped_size()) {}
   ~SimpleBufferHandle() override {}
 
   size_t size() const override { return size_; }
@@ -50,8 +53,16 @@ class SimpleBufferHandle final : public VideoCaptureBufferPool::BufferHandle {
     return gfx::SHARED_MEMORY_BUFFER;
   }
   ClientBuffer AsClientBuffer() override { return nullptr; }
+  base::PlatformFile AsPlatformFile() override {
+#if defined(OS_POSIX)
+    return shared_memory_.handle().fd;
+#else
+    return shared_memory_.handle();
+#endif
+  }
 
  private:
+  const base::SharedMemory& shared_memory_;
   void* const data_;
   const size_t size_;
 };
@@ -69,7 +80,8 @@ class GpuMemoryBufferBufferHandle
                                  gmb_->GetFormat())]),
         size_(size) {
     DCHECK(gmb && !gmb_->IsMapped());
-    gmb_->Map(data_.get());
+    if (gmb_->GetHandle().type == gfx::SHARED_MEMORY_BUFFER)
+      gmb_->Map(data_.get());
   }
   ~GpuMemoryBufferBufferHandle() override { gmb_->Unmap(); }
 
@@ -79,6 +91,10 @@ class GpuMemoryBufferBufferHandle
     return gmb_->GetHandle().type;
   }
   ClientBuffer AsClientBuffer() override { return gmb_->AsClientBuffer(); }
+  base::PlatformFile AsPlatformFile() override {
+    NOTIMPLEMENTED();
+    return base::PlatformFile();
+  }
 
  private:
   gfx::GpuMemoryBuffer* const gmb_;
@@ -95,8 +111,7 @@ class VideoCaptureBufferPool::SharedMemTracker final : public Tracker {
   size_t mapped_size() const override { return shared_memory_.mapped_size(); }
 
   scoped_ptr<BufferHandle> GetBufferHandle() override {
-    return make_scoped_ptr(
-        new SimpleBufferHandle(shared_memory_.memory(), mapped_size()));
+    return make_scoped_ptr(new SimpleBufferHandle(shared_memory_));
   }
 
   bool ShareToProcess(base::ProcessHandle process_handle,