cc: Set sync token on resource even if context is lost.

cc/test/test_web_graphics_context_3d.cc

Index: cc/test/test_web_graphics_context_3d.cc
diff --git a/cc/test/test_web_graphics_context_3d.cc b/cc/test/test_web_graphics_context_3d.cc
index 8f690b735ecd3c760e5fb984097739a8af3bbdd6..bf7387a3dc866691a2b6ecd227b7a28da8d27aea 100644
--- a/cc/test/test_web_graphics_context_3d.cc
+++ b/cc/test/test_web_graphics_context_3d.cc
@@ -646,6 +646,10 @@ GLuint64 TestWebGraphicsContext3D::insertFenceSync() {
 
 void TestWebGraphicsContext3D::genSyncToken(GLuint64 fence_sync,
                                             GLbyte* sync_token) {
+  // Don't return a valid sync token if context is lost. This matches behavior
+  // of CommandBufferProxyImpl.
+  if (context_lost_)
+    return;
   gpu::SyncToken sync_token_data(gpu::CommandBufferNamespace::GPU_IO, 0,
                                  gpu::CommandBufferId(), fence_sync);
   sync_token_data.SetVerifyFlush();