DevTools: Fix hitCount calculation for CPU profiles.

BUG=890467

Change-Id: Ie0e7fc413c068a83c9e225c63bc3e3abdebf3120
Reviewed-on: https://chromium-review.googlesource.com/1252636
Commit-Queue: Alexei Filippov <alph@chromium.org>
Reviewed-by: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Reviewed-by: Paul Irish <paulirish@chromium.org>
Cr-Commit-Position: refs/heads/master@{#595536}

third_party/WebKit/LayoutTests/http/tests/devtools/profiler/cpu-profiler-parsing-no-hitcounts-expected.txt

+Tests profile without hitCounts is parsed correctly.
+
+Profile tree:
+  (root) id:1 total:5 self:0 depth:-1
+    (garbage collector) id:2 total:1 self:1 depth:0
+    foo id:3 total:4 self:1 depth:0
+      bar id:4 total:3 self:3 depth:1
+
+samples: 4, 4, 3, 4, 2
+timestamps: 1.5, 1.75, 2.75, 3, 4, 4.625
+

third_party/WebKit/LayoutTests/http/tests/devtools/profiler/cpu-profiler-parsing-no-hitcounts.js

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+(async function() {
+  TestRunner.addResult(`Tests profile without hitCounts is parsed correctly.\n`);
+  await TestRunner.loadModule('cpu_profiler_test_runner');
+
+  var profile = {
+    startTime: 1000,
+    endTime: 6000,
+    nodes: [
+      {id: 1, callFrame: {functionName: '(root)'}, children: [2,3]},
+      {id: 2, callFrame: {functionName: '(garbage collector)'}},
+      {id: 3, callFrame: {functionName: 'foo'}, children: [4]},
+      {id: 4, callFrame: {functionName: 'bar'}}
+    ],
+    timeDeltas: [500, 250, 1000, 250, 1000],
+    samples: [4, 4, 3, 4, 2]
+  };
+
+  var model = new SDK.CPUProfileDataModel(profile);
+  TestRunner.addResult('Profile tree:');
+  printTree('  ', model.profileHead);
+  function printTree(padding, node) {
+    TestRunner.addResult(
+        `${padding}${node.functionName} id:${node.id} total:${node.total} self:${node.self} depth:${node.depth}`);
+    node.children.sort((a, b) => a.id - b.id).forEach(printTree.bind(null, padding + '  '));
+  }
+
+  TestRunner.addResult('\nsamples: ' + model.samples.join(', '));
+  TestRunner.addResult('timestamps: ' + model.timestamps.join(', '));
+
+  TestRunner.completeTest();
+})();

third_party/blink/renderer/devtools/front_end/sdk/CPUProfileDataModel.js

@@ -114,6 +114,7 @@ SDK.CPUProfileDataModel = class extends SDK.ProfileTreeModel {
         return !!node.callFrame.url && node.callFrame.url.startsWith('native ');
       return !!node['url'] && node['url'].startsWith('native ');
     }
+
     /**
      * @param {!Array<!Protocol.Profiler.ProfileNode>} nodes
      */
@@ -130,12 +131,29 @@ SDK.CPUProfileDataModel = class extends SDK.ProfileTreeModel {
           parentNode.children = [node.id];
       }
     }
+
+    /**
+     * @param {!Array<!Protocol.Profiler.ProfileNode>} nodes
+     * @param {!Array<number>|undefined} samples
+     */
+    function buildHitCountFromSamples(nodes, samples) {
+      if (typeof(nodes[0].hitCount) === 'number')
+        return;
+      console.assert(samples, 'Error: Neither hitCount nor samples are present in profile.');
+      for (let i = 0; i < nodes.length; ++i)
+        nodes[i].hitCount = 0;
+      for (let i = 0; i < samples.length; ++i)
+        ++nodeByIdMap.get(samples[i]).hitCount;
+    }
+
     /** @type {!Map<number, !Protocol.Profiler.ProfileNode>} */
     const nodeByIdMap = new Map();
     for (let i = 0; i < nodes.length; ++i) {
       const node = nodes[i];
       nodeByIdMap.set(node.id, node);
     }
+
+    buildHitCountFromSamples(nodes, this.samples);
     buildChildrenFromParents(nodes);
     this.totalHitCount = nodes.reduce((acc, node) => acc + node.hitCount, 0);
     const sampleTime = (this.profileEndTime - this.profileStartTime) / this.totalHitCount;