Add a new hook to WebLayerTreeView for requesting frames.

public/platform/WebLayerTreeView.h

Index: public/platform/WebLayerTreeView.h
diff --git a/public/platform/WebLayerTreeView.h b/public/platform/WebLayerTreeView.h
index 4f3c2d7ba3c06e4e864d5fb396809960e07be2ac..2eee1588bea7ddedbddeb67b5f09f72b1db6bf5e 100644
--- a/public/platform/WebLayerTreeView.h
+++ b/public/platform/WebLayerTreeView.h
@@ -105,6 +105,12 @@ public:
     // Indicates that an animation needs to be updated.
     virtual void setNeedsAnimate() = 0;
 
+    // Indicates that blink needs a BeginFrame, but that nothing might actually be dirty.
+    virtual void setNeedsBeginFrame() { }
+
+    // Indicates that blink needs a BeginFrame and to update compositor state.
+    virtual void setNeedsCompositorUpdate() { }
+
     // Indicates whether a commit is pending.
     virtual bool commitRequested() const = 0;