Limit renderer saved frames to avoid running out of fds.

content/common/host_shared_bitmap_manager.h

Index: content/common/host_shared_bitmap_manager.h
diff --git a/content/common/host_shared_bitmap_manager.h b/content/common/host_shared_bitmap_manager.h
index 439abe64d91916348bd607ae4b92f56e899e34cd..9dc7896145da562e5ceb858427365946e5b2fef6 100644
--- a/content/common/host_shared_bitmap_manager.h
+++ b/content/common/host_shared_bitmap_manager.h
@@ -65,6 +65,8 @@ class CONTENT_EXPORT HostSharedBitmapManager : public cc::SharedBitmapManager {
   void ChildDeletedSharedBitmap(const cc::SharedBitmapId& id);
   void ProcessRemoved(base::ProcessHandle process_handle);
 
+  size_t AllocatedBitmapCount() const { return handle_map_.size(); }
+
  private:
   base::Lock lock_;