NOT for review (for discussion): Query IOSurfaceIsInUse in the browser process

ui/gfx/gpu_memory_buffer.h

Index: ui/gfx/gpu_memory_buffer.h
diff --git a/ui/gfx/gpu_memory_buffer.h b/ui/gfx/gpu_memory_buffer.h
index 307fa18a728facfeadc4421f10f418486f25b3f3..1ffed0da055dfee7ff1a8daee5200df945b1c21a 100644
--- a/ui/gfx/gpu_memory_buffer.h
+++ b/ui/gfx/gpu_memory_buffer.h
@@ -89,6 +89,10 @@ class GFX_EXPORT GpuMemoryBuffer {
   // for scanout. Note that this will not impact texturing from the buffer.
   virtual void SetColorSpaceForScanout(const gfx::ColorSpace& color_space);
 
+  // Returns true if the GpuMemoryBuffer is currently being read by the
+  // WindowServer and should not be written to.
+  virtual bool IsInUseByMacOSWindowServer() const;
+
   // Returns a unique identifier associated with buffer.
   virtual GpuMemoryBufferId GetId() const = 0;