LayerTreeHostImpl knows if it has an output surface.

cc/output/delegating_renderer.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/output/delegating_renderer.h"
 
 #include <set>
 #include <string>
 #include <vector>
 
@@ skipping 94 matching lines @@
   compositor_frame.metadata = metadata;
   compositor_frame.delegated_frame_data = delegated_frame_data_.Pass();
   output_surface_->SwapBuffers(&compositor_frame);
 }
 
 void DelegatingRenderer::ReceiveSwapBuffersAck(
     const CompositorFrameAck& ack) {
   resource_provider_->ReceiveReturnsFromParent(ack.resources);
 }
 
-bool DelegatingRenderer::IsContextLost() {
-  ContextProvider* context_provider = output_surface_->context_provider();
-  if (!context_provider)
-    return false;
-  return context_provider->IsContextLost();
-}
-
 void DelegatingRenderer::DidChangeVisibility() {
   ContextProvider* context_provider = output_surface_->context_provider();
   if (!visible()) {
     TRACE_EVENT0("cc", "DelegatingRenderer::SetVisible dropping resources");
     resource_provider_->ReleaseCachedData();
     if (context_provider) {
       context_provider->DeleteCachedResources();
       context_provider->ContextGL()->Flush();
     }
   }
   // We loop visibility to the GPU process, since that's what manages memory.
   // That will allow it to feed us with memory allocations that we can act
   // upon.
   if (context_provider)
     context_provider->ContextSupport()->SetSurfaceVisible(visible());
 }
 
 }  // namespace cc