[turbolizer] Remove old links upon phase change

This CL removes the graph between phase changes. This prevents incorrect
path layouting after changing from a phase where a path is displayed that
is not a correct path in the phase we change to.

Change-Id: Iad80f49efc8d8c71600ad51432981c3a206ef9cb
Bug: v8:7327
Reviewed-on: https://chromium-review.googlesource.com/c/1397710Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58592}

tools/turbolizer/src/graph-view.ts

@@ -65,7 +65,7 @@ export class GraphView extends View implements PhaseView {
     svg.on("click", function (d) {
       view.selectionHandler.clear();
     });
-    // Listen for key events. Note that the focus handler seems 
+    // Listen for key events. Note that the focus handler seems
     // to be important even if it does nothing.
     svg
       .attr("focusable", false)
@@ -250,9 +250,13 @@ export class GraphView extends View implements PhaseView {
   }
 
   deleteContent() {
-    if (this.visibleNodes) {
-      this.updateGraphVisibility();
-    }
+    for (const n of this.graph.nodes()) {
+      n.visible = false;
+    };
+    this.graph.forEachEdge((e: Edge) => {
+      e.visible = false;
+    });
+    this.updateGraphVisibility();
   };
 
   createGraph(data, rememberedSelection) {