[Reland] Per WebViewScheduler virtual time

components/scheduler/renderer/web_view_scheduler_impl_browsertest.cc

+// Copyright 2016 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 "components/scheduler/renderer/web_view_scheduler_impl.h"
+
+#include "base/strings/utf_string_conversions.h"
+#include "content/public/renderer/render_view.h"
+#include "content/public/test/render_view_test.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/WebKit/public/web/WebLocalFrame.h"
+#include "third_party/WebKit/public/web/WebScriptSource.h"
+#include "third_party/WebKit/public/web/WebView.h"
+#include "v8/include/v8.h"
+
+namespace scheduler {
+
+// RenderViewTest-based tests crash on Android
+// http://crbug.com/187500
+#if defined(OS_ANDROID)
+#define MAYBE_WebViewSchedulerBrowserTest DISABLED_WebViewSchedulerBrowserTest
+#else
+#define MAYBE_WebViewSchedulerBrowserTest WebViewSchedulerBrowserTest
+#endif  // defined(OS_ANDROID)
+
+class MAYBE_WebViewSchedulerBrowserTest : public content::RenderViewTest {
+ public:
+  MAYBE_WebViewSchedulerBrowserTest() : content::RenderViewTest() {}
+  ~MAYBE_WebViewSchedulerBrowserTest() override {}
+
+ protected:
+  void SetUp() override {
+    content::RenderViewTest::SetUp();
+  }
+
+  void TearDown() override {
+    content::RenderViewTest::TearDown();
+  }
+
+  bool ExecuteJavaScriptAndReturnStringValue(
+      const base::string16& script, std::string* out_result);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(MAYBE_WebViewSchedulerBrowserTest);
+};
+
+bool MAYBE_WebViewSchedulerBrowserTest::ExecuteJavaScriptAndReturnStringValue(
+    const base::string16& script,
+    std::string* out_result) {
+  v8::HandleScope handle_scope(v8::Isolate::GetCurrent());
+  v8::Local<v8::Value> result = GetMainFrame()->executeScriptAndReturnValue(
+      blink::WebScriptSource(script));
+  if (result.IsEmpty() || !result->IsString())
+    return false;
+
+  v8::String::Utf8Value utf8_result(result);
+  *out_result = std::string(*utf8_result, utf8_result.length());
+  return true;
+}
+
+TEST_F(MAYBE_WebViewSchedulerBrowserTest, DOMTimersFireInExpectedOrder) {
+  ExecuteJavaScriptForTests(
+      "window.run_order = [];"
+      "window.timerFn = function(delay, value){"

[Sami, 2016/02/03 18:03:44]

nit: missing space before {

[alex clarke (OOO till 29th), 2016/02/04 15:00:10]

Done.

+      "  setTimeout(function(){ window.run_order.push(value);}, delay);"

[Sami, 2016/02/03 18:03:44]

nit: missing space before {

Same comment for all the other tests too.

[alex clarke (OOO till 29th), 2016/02/04 15:00:09]

Done.

+      "};"
+      "var one_hour = 60 * 60 * 1000;"
+      "window.timerFn(one_hour * 100, 'a');"
+      "window.timerFn(one_hour * 10, 'b');"
+      "window.timerFn(one_hour, 'c');");
+
+  view_->GetWebView()->scheduler()->enableVirtualTime();
+  base::TimeTicks start = base::TimeTicks::Now();
+  ProcessPendingMessages();
+  base::TimeTicks end = base::TimeTicks::Now();
+
+  std::string result;
+  EXPECT_TRUE(ExecuteJavaScriptAndReturnStringValue(
+      base::ASCIIToUTF16("window.run_order.join(', ')"), &result));
+  EXPECT_EQ("c, b, a", result);
+
+  base::TimeDelta elapsed_time = end - start;
+  // Normally the above JS would take 100 hours to run, but thanks to timer

[Sami, 2016/02/03 18:03:44]

nit: The JS runs pretty much instantly but the timer callbacks will take 100h to
fire.

[alex clarke (OOO till 29th), 2016/02/04 15:00:09]

Done.

+  // fast forwarding we can run it in milliseconds.  Note I've used 1s here to
+  // try and avoid a flaky test.
+  EXPECT_LT(elapsed_time, base::TimeDelta::FromSeconds(1));

[Sami, 2016/02/03 18:03:44]

One second may be a little too optimistic for Android :P

[Sami, 2016/02/05 13:54:34]

Should we bump this to 10s to increase the flakiness margin a bit? Anything
smaller than an hour should do, right?

[alex clarke (OOO till 29th), 2016/02/05 15:20:39]

Done.

+}
+
+TEST_F(MAYBE_WebViewSchedulerBrowserTest, SetInterval) {
+  ExecuteJavaScriptForTests(
+      "window.run_order = [];"
+      "window.count = 10;"
+      "window.interval_handle = setInterval(function(){"
+      "  if (--window.count == 0) {"
+      "     clearInterval(window.interval_handle);"
+      "  }"
+      "  window.run_order.push(window.count);"
+      "}, 1000);"
+      "setTimeout(function(){ window.run_order.push('timer');}, 1500);");
+
+  view_->GetWebView()->scheduler()->enableVirtualTime();
+  ProcessPendingMessages();
+
+  std::string result;
+  EXPECT_TRUE(ExecuteJavaScriptAndReturnStringValue(
+      base::ASCIIToUTF16("window.run_order.join(', ')"), &result));
+  // If virtual time is not supplied to TimeBase then the setInterval won't

[Sami, 2016/02/03 18:03:44]

Did you mean blink::TimerBase?

[alex clarke (OOO till 29th), 2016/02/04 15:00:09]

Done.

+  // fire 10x.
+  EXPECT_EQ("9, timer, 8, 7, 6, 5, 4, 3, 2, 1, 0", result);
+}
+
+TEST_F(MAYBE_WebViewSchedulerBrowserTest, AllowVirtualTimeToAdvance) {
+  ExecuteJavaScriptForTests(
+      "window.run_order = [];"
+      "window.timerFn = function(delay, value){"
+      "  setTimeout(function(){ window.run_order.push(value);}, delay);"
+      "};"
+      "window.timerFn(100, 'a');"
+      "window.timerFn(10, 'b');"
+      "window.timerFn(1, 'c');");
+
+  view_->GetWebView()->scheduler()->enableVirtualTime();
+  view_->GetWebView()->scheduler()->setAllowVirtualTimeToAdvance(false);
+  ProcessPendingMessages();

[Sami, 2016/02/03 18:03:44]

If the thread gets descheduled, we might end up running some of the timers,
right? Then again if we set the timeout really high we won't be testing anything
here. I wonder if there's a way to make this more reliable?

[alex clarke (OOO till 29th), 2016/02/04 15:00:09]

As discussed offline I think we're OK because if virtual time was broken, then
DOMTimersFireInExpectedOrder would break too.

+
+  std::string result;
+  EXPECT_TRUE(ExecuteJavaScriptAndReturnStringValue(
+      base::ASCIIToUTF16("window.run_order.join(', ')"), &result));
+  EXPECT_EQ("", result);
+
+  view_->GetWebView()->scheduler()->setAllowVirtualTimeToAdvance(true);
+  ProcessPendingMessages();
+
+  EXPECT_TRUE(ExecuteJavaScriptAndReturnStringValue(
+      base::ASCIIToUTF16("window.run_order.join(', ')"), &result));
+  EXPECT_EQ("c, b, a", result);
+}
+
+TEST_F(MAYBE_WebViewSchedulerBrowserTest, Normal_NonVirtualTime) {
+  ExecuteJavaScriptForTests(
+      "window.run_order = [];"
+      "window.timerFn = function(delay, value){"
+      "  setTimeout(function(){ window.run_order.push(value);}, delay);"
+      "};"
+      "window.timerFn(20, 'a');"
+      "window.timerFn(10, 'b');"
+      "window.timerFn(1, 'c');");
+
+  msg_loop_.task_runner()->PostDelayedTask(
+      FROM_HERE, base::MessageLoop::QuitWhenIdleClosure(),
+      base::TimeDelta::FromMilliseconds(30));
+  msg_loop_.Run();
+
+  std::string result;
+  EXPECT_TRUE(ExecuteJavaScriptAndReturnStringValue(
+      base::ASCIIToUTF16("window.run_order.join(', ')"), &result));
+  EXPECT_EQ("c, b, a", result);
+}
+

[Sami, 2016/02/03 18:03:44]

Should we have a test that combines throttling and virtual time? A test with a
subframe might be a good sanity check too.

[alex clarke (OOO till 29th), 2016/02/04 15:00:09]

We have a unit test RepeatingTimer_PageInBackground_MeansNothingForFirtualTime 
which checks what happens here (the two do not co-exist).

Do we need to repeat the test here?

[Sami, 2016/02/05 13:54:34]

Ah okay, that should be sufficient.

[alex clarke (OOO till 29th), 2016/02/05 15:20:39]

Acknowledged.

+}  // namespace scheduler