Input latency performance test that uses tracing.

chrome/test/perf/rendering/latency_tests.cc

Index: chrome/test/perf/rendering/latency_tests.cc
diff --git a/chrome/test/perf/rendering/latency_tests.cc b/chrome/test/perf/rendering/latency_tests.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a9feca403ad46784500e9f55cc35c26a0ddfba82
--- /dev/null
+++ b/chrome/test/perf/rendering/latency_tests.cc
@@ -0,0 +1,614 @@
+// Copyright (c) 2011 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 "base/command_line.h"
+#include "base/file_util.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/path_service.h"
+#include "base/string_number_conversions.h"
+#include "base/stringprintf.h"
+#include "base/test/test_switches.h"
+#include "base/test/trace_event_analyzer.h"
+#include "base/threading/platform_thread.h"
+#include "base/timer.h"
+#include "base/version.h"
+#include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
+#include "chrome/common/chrome_paths.h"
+#include "chrome/common/chrome_switches.h"
+#include "chrome/test/base/tracing.h"
+#include "chrome/test/base/ui_test_utils.h"
+#include "chrome/test/perf/browser_perf_test.h"
+#include "chrome/test/perf/perf_test.h"
+#include "content/browser/renderer_host/render_view_host.h"
+#include "content/browser/tab_contents/tab_contents.h"
+#include "content/public/common/content_switches.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebInputEvent.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+// Run with --vmodule=latency_tests=1 to print verbose latency info.
+
+// How is latency measured?
+//
+// The test injects mouse moves many times per frame from the browser via
+// RenderWidgetHost. Each input has a unique x coordinate. When the javascript
+// handler receives the input, it stores the coordinate for later use in the
+// requestAnimationFrame callback. In RAF, the test paints using the x
+// coordinate as a color (in software, it sets the color of a table; in webgl,
+// it executes a glClearColor). Trace events emit the color when it is picked up
+// by either UpdateRect for software or gles2_cmd_decoder/glClear for webgl.
+//
+// Each UpdateRect (software) or SwapBuffers (webgl) is considered to be a frame
+// boundary that will be used to measure latency in number of frames. Starting
+// from a frame boundary Y, the test first determines what mouse x coordinate
+// was represented by the color at that frame boundary. Then, the test walks
+// backward through the trace events to find the input event matching that
+// x coordinate. Then, the test find the nearest frame boundary X to the input
+// event (may be before or after). The number of frame boundaries is then
+// counted between X and Y to determine the input latency.
+//
+// By injecting mouse moves many times per frame, we reduce flakiness in the
+// finding of the nearest frame boundary.
+//
+// This test only measures the latency introduced by chrome code -- it does not
+// measure latency introduced by mouse drivers or the GL driver or the OS window
+// manager. The actual latency seen by a user is more than what is reported by
+// this test.
+//
+// Current modes:
+// - Software RAF
+// - WebGL RAF
+
+namespace {
+
+using namespace trace_analyzer;
+
+enum LatencyTestMode {
+  kWebGL,
+  kSoftware
+};
+
+enum LatencyTestFlags {
+  kInputHeavy   = 1 << 0,
+  kInputDirty   = 1 << 1,
+  kRafHeavy     = 1 << 2,
+  kPaintHeavy   = 1 << 3
+};
+
+const int kWebGLCanvasWidth = 10;
+const int kNumFrames = 80;
+const int kInputsPerFrame = 16;
+// Magic number to identify certain glClear events.
+const int kClearColorGreen = 137;
+const int kMouseY = 5;
+
+// Don't analyze begin frames that may be inaccurate. Latencies can be as high
+// as 5 frames or so, so skip the first 6 frames to get more accurate results.
+const int kIgnoreBeginFrames = 6;
+// Don't analyze end frames that may be inaccurate.
+const int kIgnoreEndFrames = 4;
+// Minimum frames to produce an answer.
+const int kMinimumFramesForAnalysis = 5;
+
+class LatencyTest : public BrowserPerfTest {
+ public:
+  LatencyTest() :
+      query_instant_(Query(EVENT_PHASE) ==
+                     Query::Phase(TRACE_EVENT_PHASE_INSTANT)),
+      // These queries are initialized in RunTest.
+      query_swaps_(Query::Bool(false)),
+      query_inputs_(Query::Bool(false)),
+      query_blits_(Query::Bool(false)),
+      query_clears_(Query::Bool(false)),
+      mouse_x_(0),
+      tab_width_(0),
+      delay_time_us_(0),
+      num_frames_(0),
+      verbose_(false),
+      test_flags_(0) {}
+
+  virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE;
+
+  std::vector<int> GetAllBehaviors();
+
+  // Run test with specified |mode| and |behaviors|.
+  // |mode| can be webgl or software.
+  // |behaviors| is a list of combinations of LatencyTestFlags.
+  void RunTest(LatencyTestMode mode, const std::vector<int>& behaviors);
+
+ private:
+  void RunTestInternal(const std::string& test_url,
+                       bool send_inputs,
+                       int input_delay_us);
+
+  double CalculateLatency();
+
+  std::string GetModeString() {
+    switch (mode_) {
+      case kWebGL:
+        return "webgl";
+      case kSoftware:
+        return "software";
+    }
+  }
+
+  std::string GetTraceName(int flags);
+
+  std::string GetUrlModeString(int flags);
+
+  std::string GetUrl(int flags);
+
+  int GetMeanFrameTimeMicros() const;
+
+  void SendInput();
+
+  void PrintEvents(const TraceEventVector& events);
+
+  // Path to html file.
+  FilePath test_path_;
+
+  // Query INSTANT events.
+  Query query_instant_;
+
+  // Query "swaps" which is SwapBuffers for GL and UpdateRect for software.
+  Query query_swaps_;
+
+  // Query mouse input entry events in browser process (ForwardMouseEvent).
+  Query query_inputs_;
+
+  // Query GL blits for the WebGL canvas -- represents the compositor consuming
+  // the WebGL contents for display.
+  Query query_blits_;
+
+  // Query glClear calls with mouse coordinate as clear color.
+  Query query_clears_;
+
+  // For searching trace data.
+  scoped_ptr<TraceAnalyzer> analyzer_;
+
+  // Current mouse x coordinate for injecting events.
+  int mouse_x_;
+
+  // Width of window containing our tab.
+  int tab_width_;
+
+  // Timer for injecting mouse events periodically.
+  base::RepeatingTimer<LatencyTest> timer_;
+
+  // Mode: webgl or software

[Paweł Hajdan Jr., 2011/12/22 08:08:39]

nit: Dot at the end.

[jbates, 2011/12/22 19:39:34]

Done.

+  LatencyTestMode mode_;
+
+  // Delay time for javascript test code. Typically 2 x frame duration. Used
+  // to spin-wait in the javascript input handler and requestAnimationFrame.
+  int delay_time_us_;
+
+  // Number of frames to render from the html test code.
+  int num_frames_;
+
+  // Map from test flags combination to the calculated mean latency.
+  std::map<int, double> latencies_;
+
+  // Whether to print more verbose output.
+  bool verbose_;
+
+  // Current test flags combination, determining the behavior of the test.
+  int test_flags_;
+};
+
+void LatencyTest::SetUpCommandLine(CommandLine* command_line) {
+  BrowserPerfTest::SetUpCommandLine(command_line);
+  // This enables DOM automation for tab contents.
+  EnableDOMAutomation();
+  if (CommandLine::ForCurrentProcess()->
+      HasSwitch(switches::kEnableThreadedCompositing)) {
+    command_line->AppendSwitch(switches::kEnableThreadedCompositing);
+  }
+  // Default behavior is to thumbnail the tab after 0.5 seconds, causing
+  // a nasty frame hitch and disturbing the latency test. Fix that:
+  command_line->AppendSwitch(switches::kEnableInBrowserThumbnailing);
+  command_line->AppendSwitch(switches::kDisableBackgroundNetworking);
+}
+
+std::vector<int> LatencyTest::GetAllBehaviors() {
+  std::vector<int> behaviors;
+  int max_behaviors = kInputHeavy | kInputDirty | kRafHeavy | kPaintHeavy;
+  for (int i = 0; i <= max_behaviors; ++i)
+    behaviors.push_back(i);
+  return behaviors;
+}
+
+void LatencyTest::RunTest(LatencyTestMode mode,
+                          const std::vector<int>& behaviors) {
+  mode_ = mode;
+  verbose_ = (logging::GetVlogLevel("latency_tests") > 0);
+
+  // Construct queries for searching trace events via TraceAnalyzer.
+  if (mode_ == kWebGL) {
+    query_swaps_ = query_instant_ &&
+        Query(EVENT_NAME) == Query::String("SwapBuffers") &&
+        Query(EVENT_ARG, "width") != Query::Int(kWebGLCanvasWidth);
+  } else if (mode_ == kSoftware) {
+    // Software updates need to have x=0 and y=0 to contain the input color.
+    query_swaps_ = query_instant_ &&
+        Query(EVENT_NAME) == Query::String("UpdateRect") &&
+        Query(EVENT_ARG, "x+y") == Query::Int(0);
+  }
+  query_inputs_ = query_instant_ &&
+      Query(EVENT_NAME) == Query::String("MouseEventBegin");
+  query_blits_ = query_instant_ &&
+      Query(EVENT_NAME) == Query::String("DoBlit") &&
+      Query(EVENT_ARG, "width") == Query::Int(kWebGLCanvasWidth);
+  query_clears_ = query_instant_ &&
+      Query(EVENT_NAME) == Query::String("DoClear") &&
+      Query(EVENT_ARG, "green") == Query::Int(kClearColorGreen);
+  Query query_width_swaps = query_swaps_;
+  if (mode_ == kSoftware) {
+    query_width_swaps = query_instant_ &&
+        Query(EVENT_NAME) == Query::String("UpdateRectWidth") &&
+        Query(EVENT_ARG, "width") > Query::Int(kWebGLCanvasWidth);
+  }
+
+  // Set path to test html.
+  ASSERT_TRUE(PathService::Get(chrome::DIR_TEST_DATA, &test_path_));
+  test_path_ = test_path_.Append(FILE_PATH_LITERAL("perf"));
+  test_path_ = test_path_.Append(FILE_PATH_LITERAL("latency_suite.html"));
+  ASSERT_TRUE(file_util::PathExists(test_path_))
+      << "Missing test file: " << test_path_.value();
+
+  // Run once with defaults to measure the frame times.
+  delay_time_us_ = 0;
+  // kNumFrames may be very high, but we only need a few frames to measure
+  // average frame times.
+  num_frames_ = 30;
+  int initial_flags = 0;
+  if (mode_ == kSoftware) {
+    // For the first run, run software with kPaintHeavy (which toggles the
+    // background color every frame) to force an update each RAF. Otherwise it
+    // won't trigger an UpdateRect each frame and we won't be able to measure
+    // framerate, because there are no inputs during the first run.
+    initial_flags = static_cast<int>(kPaintHeavy);
+  }
+  RunTestInternal(GetUrl(initial_flags), false, 0);
+
+  // Get width of tab so that we know the limit of x coordinates for the
+  // injected mouse inputs.
+  const TraceEvent* swap_event = analyzer_->FindOneEvent(query_width_swaps);
+  ASSERT_TRUE(swap_event);
+  tab_width_ = swap_event->GetKnownArgAsInt("width");
+  // Keep printf output clean by limiting input coords to three digits:
+  tab_width_ = (tab_width_ < 1000) ? tab_width_ : 999;
+  // Sanity check the tab_width -- it should be more than 100 pixels.
+  EXPECT_GT(tab_width_, 100);
+
+  int mean_frame_time_us = GetMeanFrameTimeMicros();
+  if (verbose_)
+    printf("Mean frame time micros = %d\n", mean_frame_time_us);
+  // Delay time is 2x the average frame time.
+  delay_time_us_ = 2 * mean_frame_time_us;
+  // Calculate delay time between inputs based on the measured frame time.
+  // This prevents flooding the browser with more events than we need if the
+  // test is running very slow (such as on a VM).
+  int delay_us = mean_frame_time_us / kInputsPerFrame;
+
+  // Reset num_frames_ for actual test runs.
+  num_frames_ = kNumFrames;
+
+  // Run input latency test with each requested behavior.
+  for (size_t i = 0; i < behaviors.size(); ++i) {
+    test_flags_ = behaviors[i];
+    std::string url = GetUrl(test_flags_);
+    printf("=============================================================\n");
+    if (verbose_)
+      printf("Mode: %s\n", GetUrlModeString(i).c_str());
+    printf("URL: %s\n", url.c_str());
+
+    // Do the actual test with input events.
+    RunTestInternal(url, true, delay_us);
+    latencies_[test_flags_] = CalculateLatency();
+  }
+
+  // Print summary if more than 1 behavior was tested in this run. This is only
+  // for manual test runs for human reabable results, not for perf bots.
+  if (behaviors.size() > 1) {
+    printf("#############################################################\n");
+    printf("## %s\n", GetModeString().c_str());
+    if (verbose_) {
+      printf("Latency, behavior:\n");
+      for (size_t i = 0; i < behaviors.size(); ++i) {
+        printf("%.1f, %s%s%s%s\n", latencies_[behaviors[i]],
+               (i & kInputHeavy) ? "InputHeavy " : "",
+               (i & kInputDirty) ? "InputDirty " : "",
+               (i & kRafHeavy) ? "RafHeavy " : "",
+               (i & kPaintHeavy) ? "PaintHeavy " : "");
+      }
+    }
+    printf("Latencies for tests: ");
+    for (size_t i = 0; i < behaviors.size(); ++i) {
+      printf("%.1f%s", latencies_[behaviors[i]],
+             (i < behaviors.size() - 1) ? ", " : "");
+    }
+    printf("\n");
+    printf("#############################################################\n");
+  }
+}
+
+void LatencyTest::RunTestInternal(const std::string& test_url,
+                                  bool send_inputs,
+                                  int input_delay_us) {
+  mouse_x_ = 0;
+
+  ASSERT_TRUE(tracing::BeginTracing("test_gpu,test_latency"));
+
+  ui_test_utils::NavigateToURLWithDisposition(
+      browser(), GURL(test_url), CURRENT_TAB,
+      ui_test_utils::BROWSER_TEST_NONE);
+
+  // Start sending mouse inputs.
+  if (send_inputs) {
+    // Round input_delay_us down to nearest milliseconds. The rounding in timer
+    // code rounds up from us to ms, so we need to do our own rounding here.
+    int input_delay_ms = input_delay_us / 1000;
+    input_delay_ms = (input_delay_ms <= 0) ? 1 : input_delay_ms;
+    timer_.Start(FROM_HERE, base::TimeDelta::FromMilliseconds(input_delay_ms),
+                 this, &LatencyTest::SendInput);
+  }
+
+  // Wait for message indicating the test has finished running.
+  ui_test_utils::DOMMessageQueue message_queue;
+  ASSERT_TRUE(message_queue.WaitForMessage(NULL));
+
+  timer_.Stop();
+
+  std::string json_events;
+  ASSERT_TRUE(tracing::EndTracing(&json_events));
+
+  analyzer_.reset(TraceAnalyzer::Create(json_events));
+  analyzer_->AssociateBeginEndEvents();
+  analyzer_->MergeAssociatedEventArgs();
+}
+
+double LatencyTest::CalculateLatency() {
+  TraceEventVector events;
+  if (mode_ == kWebGL) {
+    // Search for three types of events in WebGL mode:
+    //  - onscreen swaps.
+    //  - DoClear calls that contain the mouse x coordinate.
+    //  - mouse events.
+    analyzer_->FindEvents(query_swaps_ || query_inputs_ ||
+                          query_blits_ || query_clears_, &events);
+  } else if (mode_ == kSoftware) {
+    analyzer_->FindEvents(query_swaps_ || query_inputs_, &events);
+  } else {
+    NOTREACHED() << "invalid mode";
+  }
+
+  if (verbose_)
+    PrintEvents(events);
+
+  int swap_count = 0;
+  size_t previous_blit_pos = 0;
+  swap_count = 0;
+  std::vector<int> latencies;
+  printf("Measured latency (in number of frames) for each frame:\n");
+  for (size_t i = 0; i < events.size(); ++i) {
+    if (query_swaps_.Evaluate(*events[i])) {
+      // Compositor context swap buffers.
+      ++swap_count;
+      // Don't analyze first few swaps, because they are filling the rendering
+      // pipeline and may be unstable.
+      if (swap_count > kIgnoreBeginFrames) {
+        int mouse_x = 0;
+        if (mode_ == kWebGL) {
+          // Trace backwards through the events to find the input event that
+          // matches the glClear that was presented by this SwapBuffers.
+
+          // Step 1: Find the last blit (which will be the WebGL blit).
+          size_t blit_pos = 0;
+          EXPECT_TRUE(FindLastOf(events, query_blits_, i, &blit_pos));
+          // Skip this SwapBuffers if the blit has already been consumed by a
+          // previous SwapBuffers. This means the current frame did not receive
+          // an update from WebGL.
+          EXPECT_GT(blit_pos, previous_blit_pos);
+          if (blit_pos == previous_blit_pos) {
+            if (verbose_)
+              printf(" %03d: ERROR\n", swap_count);
+            else
+              printf(" ERROR");
+            continue;
+          }
+          previous_blit_pos = blit_pos;
+
+          // Step 2: find the last clear from the WebGL blit. This will be the
+          // value of the latest mouse input that has affected this swap.
+          size_t clear_pos = 0;
+          EXPECT_TRUE(FindLastOf(events, query_clears_, blit_pos, &clear_pos));
+          mouse_x = events[clear_pos]->GetKnownArgAsInt("red");
+        } else if (mode_ == kSoftware) {
+          // The software path gets the mouse_x directly from the DIB colors.
+          mouse_x = events[i]->GetKnownArgAsInt("color");
+        }
+
+        // Find the corresponding mouse input.
+        size_t input_pos = 0;
+        Query query_mouse_event = query_inputs_ &&
+            Query(EVENT_ARG, "x") == Query::Int(mouse_x);
+        EXPECT_TRUE(FindLastOf(events, query_mouse_event, i, &input_pos));
+
+        // Step 4: Find the nearest onscreen SwapBuffers to this input event.
+        size_t closest_swap = 0;
+        size_t second_closest_swap = 0;
+        EXPECT_TRUE(FindClosest(events, query_swaps_, input_pos,
+                                       &closest_swap, &second_closest_swap));
+        int latency = CountMatches(events, query_swaps_, closest_swap, i);
+        latencies.push_back(latency);
+        if (verbose_)
+          printf(" %03d: %d\n", swap_count, latency);
+        else
+          printf(" %d", latency);
+      }
+    }
+  }
+  printf("\n");
+
+  size_t ignoreEndFrames = static_cast<size_t>(kIgnoreEndFrames);
+  bool haveEnoughFrames = latencies.size() >
+      ignoreEndFrames + static_cast<size_t>(kMinimumFramesForAnalysis);
+  EXPECT_TRUE(haveEnoughFrames);
+  if (!haveEnoughFrames)
+    return 0.0;
+
+  double mean_latency = 0.0;
+  // Skip last few frames, because they may be unreliable.
+  size_t num_consider = latencies.size() - ignoreEndFrames;
+  for (size_t i = 0; i < num_consider; ++i)
+    mean_latency += static_cast<double>(latencies[i]);
+  mean_latency /= static_cast<double>(num_consider);
+  printf("Mean latency = %f\n", mean_latency);
+
+  double mean_error = 0.0;
+  for (size_t i = 0; i < num_consider; ++i) {
+    double offset = fabs(mean_latency - static_cast<double>(latencies[i]));
+    mean_error = (offset > mean_error) ? offset : mean_error;
+  }
+
+  std::string trace_name = GetTraceName(test_flags_);
+  std::string mean_and_error = base::StringPrintf("%f,%f", mean_latency,
+                                                  mean_error);
+  perf_test::PrintResultMeanAndError(GetModeString(), "", trace_name,
+                                     mean_and_error, "frames", true);
+  return mean_latency;
+}
+
+std::string LatencyTest::GetTraceName(int flags) {
+  if (flags == 0)
+    return "simple";
+  std::string name;
+  if (flags & kInputHeavy)
+    name += "ih";
+  if (flags & kInputDirty)
+    name += std::string(name.empty()? "" : "_") + "id";
+  if (flags & kRafHeavy)
+    name += std::string(name.empty()? "" : "_") + "rh";
+  if (flags & kPaintHeavy)
+    name += std::string(name.empty()? "" : "_") + "ph";
+  return name;
+}
+
+std::string LatencyTest::GetUrlModeString(int flags) {
+  std::string mode = "&mode=" + GetModeString();
+  if (flags & kInputHeavy)
+    mode += "&inputHeavy";
+  if (flags & kInputDirty)
+    mode += "&inputDirty";
+  if (flags & kRafHeavy)
+    mode += "&rafHeavy";
+  if (flags & kPaintHeavy)
+    mode += "&paintHeavy";
+  return mode;
+}
+
+std::string LatencyTest::GetUrl(int flags) {
+  std::string test_url =
+      net::FilePathToFileURL(test_path_).possibly_invalid_spec();
+  test_url += "?numFrames=" + base::IntToString(num_frames_);
+  test_url += "&canvasWidth=" + base::IntToString(kWebGLCanvasWidth);
+  test_url += "&clearColorGreen=" + base::IntToString(kClearColorGreen);
+  test_url += "&delayTimeMS=" + base::IntToString(delay_time_us_ / 1000);
+  test_url += "&y=" + base::IntToString(kMouseY);
+  return test_url + GetUrlModeString(flags);
+}
+
+int LatencyTest::GetMeanFrameTimeMicros() const {
+  TraceEventVector events;
+  // Search for compositor swaps (or UpdateRects in the software path).
+  analyzer_->FindEvents(query_swaps_, &events);
+  RateStats stats;
+  bool success = GetRateStats(events, &stats);
+  // ASSERT_TRUE doesn't work in methods that return non-void.
+  EXPECT_TRUE(success);
+  CHECK(success);

[Paweł Hajdan Jr., 2011/12/22 08:08:39]

Are you sure you want to crash the test? This is a browser test so it will
affect only a single test and not the entire test binary, but still if this gets
flaky the test would have to be disabled.

[jbates, 2011/12/22 19:39:34]

Done. (Changed to void method with ASSERT_TRUE.)

+
+  // Check that the number of swaps is close to kNumFrames.
+  EXPECT_LT(num_frames_ - num_frames_ / 4, static_cast<int>(events.size()));
+  return static_cast<int>(stats.mean_us);
+}
+
+void LatencyTest::SendInput() {
+  RenderViewHost* rvh = browser()->GetSelectedTabContentsWrapper()->
+      tab_contents()->render_manager_for_testing()->current_host();
+  WebKit::WebMouseEvent mouse_event;
+  mouse_event.movementX = 1;
+  mouse_x_ += mouse_event.movementX;
+  // Wrap mouse_x_ when it's near the edge of the tab.
+  if (mouse_x_ > tab_width_ - 5)
+    mouse_x_ = 1;
+  mouse_event.x = mouse_event.windowX = mouse_x_;
+  // Set y coordinate to be a few pixels down from the top of the window,
+  // so that it is between the top and bottom of the canvas.
+  mouse_event.y = mouse_event.windowY = 5;
+  mouse_event.type = WebKit::WebInputEvent::MouseMove;
+  TRACE_EVENT_INSTANT1("test_latency", "MouseEventBegin", "x", mouse_x_);
+  rvh->ForwardMouseEvent(mouse_event);
+}
+
+void LatencyTest::PrintEvents(const TraceEventVector& events) {
+  bool is_software = (mode_ == kSoftware);
+  int swap_count = 0;
+  for (size_t i = 0; i < events.size(); ++i) {
+    if (events[i]->name == "MouseEventBegin") {
+      printf("%03d ", events[i]->GetKnownArgAsInt("x"));
+    } else if (events[i]->name == "DoClear") {
+      printf("Clr%03d ", events[i]->GetKnownArgAsInt("red"));
+    } else if (events[i]->name == "DoBlit") {
+      // WebGL context swap buffers.
+      printf("BLT ");
+    } else if (events[i]->name == "SwapBuffers") {
+      // Compositor context swap buffers.
+      ++swap_count;
+      printf("|\nframe %03d: ", swap_count + 1);
+    } else if (is_software && events[i]->name == "UpdateRect") {
+      ++swap_count;
+      printf("(%d)|\nframe %03d: ",
+              events[i]->GetKnownArgAsInt("color"), swap_count + 1);
+    }
+  }
+  printf("\n");
+}
+
+////////////////////////////////////////////////////////////////////////////////
+/// Tests
+
+// For manual testing only, run all input latency tests and print summary.
+IN_PROC_BROWSER_TEST_F(LatencyTest, DISABLED_LatencyWebGLAll) {
+  RunTest(kWebGL, GetAllBehaviors());
+}
+
+// For manual testing only, run all input latency tests and print summary.
+IN_PROC_BROWSER_TEST_F(LatencyTest, DISABLED_LatencySoftwareAll) {
+  RunTest(kSoftware, GetAllBehaviors());
+}
+
+// Define a latency test for WebGL and Software.
+// |prefix| can optionally be DISABLED_ or FLAKY_, etc.
+#define LATENCY_TEST(prefix, name, behavior) \

[Paweł Hajdan Jr., 2011/12/22 08:08:39]

Why a macro? I think gtest has parametrized tests, and I remember we should have
a macro for parametrized IN_PROC_BROWSER_TEST.

[jbates, 2011/12/22 19:39:34]

Done.

+  IN_PROC_BROWSER_TEST_F(LatencyTest, prefix ## LatencyWebGL ## name) { \
+    std::vector<int> behaviors; \
+    behaviors.push_back(behavior); \
+    RunTest(kWebGL, behaviors); \
+  } \
+  IN_PROC_BROWSER_TEST_F(LatencyTest, prefix ## LatencySoftware ## name) { \
+    std::vector<int> behaviors; \
+    behaviors.push_back(behavior); \
+    RunTest(kSoftware, behaviors); \
+  }
+
+LATENCY_TEST(, _simple, 0);
+LATENCY_TEST(, _ih, kInputHeavy);
+LATENCY_TEST(, _ih_id_rh, kInputHeavy | kInputDirty | kRafHeavy);
+LATENCY_TEST(, _id_ph, kInputDirty | kPaintHeavy);
+LATENCY_TEST(, _id_rh_ph, kInputDirty | kRafHeavy | kPaintHeavy);
+LATENCY_TEST(, _id_ih_rh_ph, kInputDirty | kInputHeavy | kRafHeavy |
+                             kPaintHeavy);
+
+}  // namespace anonymous

[Paweł Hajdan Jr., 2011/12/22 08:08:39]

nit: We usually just write "// namespace".

[jbates, 2011/12/22 19:39:34]

Done.