Reset the nesting level for setInterval after completion.

third_party/WebKit/Source/core/frame/DOMTimerTest.cpp

Index: third_party/WebKit/Source/core/frame/DOMTimerTest.cpp
diff --git a/third_party/WebKit/Source/core/frame/DOMTimerTest.cpp b/third_party/WebKit/Source/core/frame/DOMTimerTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..787befa6f8fd28728e0989d1ff2f74c89b47b847
--- /dev/null
+++ b/third_party/WebKit/Source/core/frame/DOMTimerTest.cpp
@@ -0,0 +1,133 @@
+// Copyright 2017 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.
+
+#include "core/frame/DOMTimer.h"
+
+#include <vector>
+
+#include "bindings/core/v8/ScriptController.h"
+#include "core/dom/Document.h"
+#include "core/layout/LayoutTestHelper.h"
+#include "platform/testing/TestingPlatformSupport.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using testing::DoubleNear;
+using testing::ElementsAreArray;
+using testing::Matcher;
+
+namespace blink {
+
+namespace {
+
+class DOMTimerTest : public RenderingTest {
+ public:
+  ScopedTestingPlatformSupport<TestingPlatformSupportWithMockScheduler>
+      m_platform;
+
+  // Expected time between each iterator for setInterval(..., 1) or nested
+  // setTimeout(..., 1) are 1, 1, 1, 1, 4, 4, ... as a minumum clamp of 4m
+  // is applied from the 5th iteration onwards.
+  const std::vector<Matcher<double>> kExpectedTimings = {
+      DoubleNear(1., 0.000001), DoubleNear(1., 0.000001),
+      DoubleNear(1., 0.000001), DoubleNear(1., 0.000001),
+      DoubleNear(4., 0.000001), DoubleNear(4., 0.000001),
+  };
+
+  void SetUp() override {
+    m_platform->setAutoAdvanceNowToPendingTasks(true);
+    // Advance timer manually as RenderingTest expects the time to be non-zero.
+    m_platform->advanceClockSeconds(1.);
+    RenderingTest::SetUp();
+    // Advance timer again as otherwise the time between the first call to
+    // setInterval and it running will be off by 5us.
+    m_platform->advanceClockSeconds(1);
+    document().settings()->setScriptEnabled(true);
+  }
+
+  v8::Local<v8::Value> EvalExpression(const char* expr) {
+    return document().frame()->script().executeScriptInMainWorldAndReturnValue(
+        ScriptSourceCode(expr));
+  }
+
+  Vector<double> toDoubleArray(v8::Local<v8::Value> value,
+                               v8::HandleScope& scope) {
+    NonThrowableExceptionState exceptionState;
+    return toImplArray<Vector<double>>(value, 0, scope.GetIsolate(),
+                                       exceptionState);
+  }
+
+  void ExecuteScriptAndWaitUntilIdle(const char* scriptText) {
+    ScriptSourceCode script(scriptText);
+    document().frame()->script().executeScriptInMainWorld(script);
+    m_platform->runUntilIdle();
+  }
+};
+
+const char* kSetTimeoutScriptText =
+    "var id;"
+    "var last = performance.now();"
+    "var times = [];"
+    "function nestSetTimeouts() {"
+    "  var current = performance.now();"
+    "  var elapsed = current - last;"
+    "  last = current;"
+    "  times.push(elapsed);"
+    "  if (times.length < 6) {"
+    "    setTimeout(nestSetTimeouts, 1);"
+    "  }"
+    "}"
+    "setTimeout(nestSetTimeouts, 1);";
+
+TEST_F(DOMTimerTest, setTimeout_ClampsAfter4Nestings) {
+  v8::HandleScope scope(v8::Isolate::GetCurrent());
+
+  ExecuteScriptAndWaitUntilIdle(kSetTimeoutScriptText);
+
+  auto times(toDoubleArray(EvalExpression("times"), scope));
+
+  EXPECT_THAT(times, ElementsAreArray(kExpectedTimings));
+}
+
+const char* kSetIntervalScriptText =
+    "var last = performance.now();"
+    "var times = [];"
+    "var id = setInterval(function() {"
+    "  var current = performance.now();"
+    "  var elapsed = current - last;"
+    "  last = current;"
+    "  times.push(elapsed);"
+    "  if (times.length > 5) {"
+    "    clearInterval(id);"
+    "  }"
+    "}, 1);";
+
+TEST_F(DOMTimerTest, setInterval_ClampsAfter4Iterations) {
+  v8::HandleScope scope(v8::Isolate::GetCurrent());
+
+  ExecuteScriptAndWaitUntilIdle(kSetIntervalScriptText);
+
+  auto times(toDoubleArray(EvalExpression("times"), scope));
+
+  EXPECT_THAT(times, ElementsAreArray(kExpectedTimings));
+}
+
+TEST_F(DOMTimerTest, setInterval_NestingResetsForLaterCalls) {
+  v8::HandleScope scope(v8::Isolate::GetCurrent());
+
+  ExecuteScriptAndWaitUntilIdle(kSetIntervalScriptText);
+
+  // Run the setIntervalScript again to verify that the clamp imposed for
+  // nesting beyond 4 levels is reset when setInterval is called again in the
+  // original scope but after the original setInterval has completed.
+  ExecuteScriptAndWaitUntilIdle(kSetIntervalScriptText);
+
+  auto times(toDoubleArray(EvalExpression("times"), scope));
+
+  EXPECT_THAT(times, ElementsAreArray(kExpectedTimings));
+}
+
+}  // namespace
+
+}  // namespace blink