Break tight coupling of VideoCaptureDeviceClient to renderer_host

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 6398f48ca7eb685a599e47bc24231cc0c0e11552..4ee7fae7a81bf467a581d80d61225b5528c47c59 100644
--- a/content/browser/renderer_host/media/video_capture_buffer_pool.cc
+++ b/content/browser/renderer_host/media/video_capture_buffer_pool.cc
@@ -16,8 +16,6 @@
 
 namespace content {
 
-const int VideoCaptureBufferPool::kInvalidId = -1;
-
 // Tracker specifics for SharedMemory.
 class VideoCaptureBufferPool::SharedMemTracker final : public Tracker {
  public:
@@ -385,7 +383,7 @@ int VideoCaptureBufferPool::ResurrectLastForProducer(
   return kInvalidId;
 }
 
-double VideoCaptureBufferPool::GetBufferPoolUtilization() const {
+double VideoCaptureBufferPool::GetBufferPoolUtilization() {
   base::AutoLock lock(lock_);
   int num_buffers_held = 0;
   for (const auto& entry : trackers_) {