Add a test checking that compositor works in a reused renderer.

content/browser/renderer_host/delegated_frame_host.cc

Index: content/browser/renderer_host/delegated_frame_host.cc
diff --git a/content/browser/renderer_host/delegated_frame_host.cc b/content/browser/renderer_host/delegated_frame_host.cc
index a844d65c25fac8c0edf4de89211ff54d819d73a6..1d4f3159c2d30687430ce896ddfeede67d91d4b5 100644
--- a/content/browser/renderer_host/delegated_frame_host.cc
+++ b/content/browser/renderer_host/delegated_frame_host.cc
@@ -779,6 +779,10 @@ DelegatedFrameHost::~DelegatedFrameHost() {
   ImageTransportFactory* factory = ImageTransportFactory::GetInstance();
   factory->GetContextFactory()->RemoveObserver(this);
 
+  // If a swap ACK was pending, it must be sent (see https://crbug.com/705548).
+  if (support_)
+    support_->RunDrawCallbacks();
+
   ResetCompositorFrameSinkSupport();
 
   factory->GetContextFactoryPrivate()