[profview] Add runtime-entry top-down tree.

Review-Url: https://codereview.chromium.org/2811953003
Cr-Commit-Position: refs/heads/master@{#44561}

tools/profview/profile-utils.js

@@ -130,6 +130,7 @@ function findNextFrame(file, stack, stackPos, step, filter) {
   while (stackPos >= 0 && stackPos < stack.length) {
     codeId = stack[stackPos];
     code = codeId >= 0 ? file.code[codeId] : undefined;
+
     if (filter) {
       let type = code ? code.type : undefined;
       let kind = code ? code.kind : undefined;
@@ -198,6 +199,31 @@ function createEmptyNode(name) {
   };
 }
 
+class RuntimeCallTreeProcessor {
+  constructor() {
+    this.tree = createEmptyNode("root");
+    this.tree.delayedExpansion = { frameList : [], ascending : false };
+  }
+
+  addStack(file, tickIndex) {
+    this.tree.ticks++;
+
+    let stack = file.ticks[tickIndex].s;
+    let i;
+    for (i = 0; i < stack.length; i += 2) {
+      let codeId = stack[i];
+      if (codeId < 0) return;
+      let code = file.code[codeId];
+      if (code.type !== "CPP" && code.type !== "SHARED_LIB") {
+        i -= 2;
+        break;
+      }
+    }
+    if (i < 0 || i >= stack.length) return;
+    addOrUpdateChildNode(this.tree, file, tickIndex, i, false);
+  }
+}
+
 class PlainCallTreeProcessor {
   constructor(filter, isBottomUp) {
     this.filter = filter;

tools/profview/profview.js

@@ -526,7 +526,8 @@ class CallTreeView {
       case "top-down":
         addOptions(this.selectAttribution, attributions, calltree.attribution);
         addOptions(this.selectCategories, [
-            { value : "none", text : "None" }
+            { value : "none", text : "None" },
+            { value : "rt-entry", text : "Runtime entries" }
         ], calltree.categories);
         addOptions(this.selectSort, [
             { value : "time", text : "Time (including children)" },
@@ -605,8 +606,13 @@ class CallTreeView {
     let stackProcessor;
     let filter = filterFromFilterId(this.currentState.callTree.attribution);
     if (mode === "top-down") {
-      stackProcessor =
-          new PlainCallTreeProcessor(filter, false);
+      if (this.currentState.callTree.categories === "rt-entry") {
+        stackProcessor =
+            new RuntimeCallTreeProcessor();
+      } else {
+        stackProcessor =
+            new PlainCallTreeProcessor(filter, false);
+      }
     } else if (mode === "function-list") {
       stackProcessor = new FunctionListTree(
           filter, this.currentState.callTree.categories === "code-type");