Enable control over frame time in SimTests

third_party/WebKit/Source/web/tests/sim/SimCompositor.h

Index: third_party/WebKit/Source/web/tests/sim/SimCompositor.h
diff --git a/third_party/WebKit/Source/web/tests/sim/SimCompositor.h b/third_party/WebKit/Source/web/tests/sim/SimCompositor.h
index 914fab152f30a91a53a67e8b88ec1ae83529e63d..de5dc1ef1c9a206096c9c02245c3596c6d677c4b 100644
--- a/third_party/WebKit/Source/web/tests/sim/SimCompositor.h
+++ b/third_party/WebKit/Source/web/tests/sim/SimCompositor.h
@@ -30,7 +30,8 @@ class SimCompositor final : public WebLayerTreeView {
 
   // Execute the BeginMainFrame processing steps, an approximation of what
   // cc::ThreadProxy::BeginMainFrame would do.
-  SimDisplayItemList beginFrame();
+  // If time is not specified a 60Hz frame rate time progression is used.
+  SimDisplayItemList beginFrame(double timeDeltaInSeconds = 0.016);
 
   bool needsBeginFrame() const { return m_needsBeginFrame; }
   bool deferCommits() const { return m_deferCommits; }