PlzNavigate: Release StreamHandle.

content/browser/frame_host/render_frame_host_impl.h

Index: content/browser/frame_host/render_frame_host_impl.h
diff --git a/content/browser/frame_host/render_frame_host_impl.h b/content/browser/frame_host/render_frame_host_impl.h
index 39f8b81db1d0a4228c6ec1401370d8b36f4eff0e..db36975b359f33f3f9c83a0d6514e1a2f025edd8 100644
--- a/content/browser/frame_host/render_frame_host_impl.h
+++ b/content/browser/frame_host/render_frame_host_impl.h
@@ -637,6 +637,10 @@ class CONTENT_EXPORT RenderFrameHostImpl
   // sending a mojo overlay factory.
   const base::UnguessableToken& GetOverlayRoutingToken();
 
+  const StreamHandle* stream_handle_for_testing() const {
+    return stream_handle_.get();
+  }
+
  protected:
   friend class RenderFrameHostFactory;
 
@@ -956,6 +960,10 @@ class CONTENT_EXPORT RenderFrameHostImpl
   // to |url|.
   void SetLastCommittedSiteUrl(const GURL& url);
 
+  // PlzNavigate: Called when the frame has consumed the StreamHandle and it
+  // can be released.
+  void OnStreamHandleConsumed(const GURL& stream_url);
+
   // For now, RenderFrameHosts indirectly keep RenderViewHosts alive via a
   // refcount that calls Shutdown when it reaches zero.  This allows each
   // RenderFrameHostManager to just care about RenderFrameHosts, while ensuring