Show max latency on client's status bar

Will later also consider storing max latency data in server

BUG=560950

Committed: https://crrev.com/e37a467453f3814a9ecb0eb6769bd7c58b61cbae
Cr-Commit-Position: refs/heads/master@{#382663}

Review URL: https://codereview.chromium.org/1811833002

Cr-Commit-Position: refs/heads/master@{#382957}

5 files changed, 129 insertions, 81 deletions

diff --git a/remoting/base/BUILD.gn b/remoting/base/BUILD.gn
index 8a039e1..b8577c1 100644
--- a/remoting/base/BUILD.gn
+++ b/remoting/base/BUILD.gn
@@ -65,7 +65,7 @@ source_set("unit_tests") {
     "rate_counter_unittest.cc",
     "rsa_key_pair_unittest.cc",
     "run_all_unittests.cc",
-    "running_average_unittest.cc",
+    "running_samples_unittest.cc",
     "test_rsa_key_pair.h",
     "typed_buffer_unittest.cc",
     "util_unittest.cc",
diff --git a/remoting/base/running_average_unittest.cc b/remoting/base/running_average_unittest.cc
deleted file mode 100644
index e731573..0000000
--- a/remoting/base/running_average_unittest.cc
+++ /dev/null
@@ -1,60 +0,0 @@
-// Copyright 2013 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 <stddef.h>
-#include <stdint.h>
-
-#include "base/macros.h"
-#include "remoting/base/running_average.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-namespace remoting {
-
-static const int64_t kTestValues[] = { 10, 20, 30, 10, 25, 16, 15 };
-
-// Average across a single element, i.e. just return the most recent.
-TEST(RunningAverageTest, OneElementWindow) {
-  RunningAverage running_average(1);
-  EXPECT_EQ(0, running_average.Average());
-
-  for (size_t i = 0; i < arraysize(kTestValues); ++i) {
-    running_average.Record(kTestValues[i]);
-    EXPECT_EQ(static_cast<double>(kTestValues[i]), running_average.Average());
-  }
-}
-
-// Average the two most recent elements.
-TEST(RunningAverageTest, TwoElementWindow) {
-  RunningAverage running_average(2);
-  EXPECT_EQ(0, running_average.Average());
-
-  for (size_t i = 0; i < arraysize(kTestValues); ++i) {
-    running_average.Record(kTestValues[i]);
-
-    double expected = kTestValues[i];
-    if (i > 0)
-      expected = (expected + kTestValues[i-1]) / 2;
-
-    EXPECT_EQ(expected, running_average.Average());
-  }
-}
-
-// Average across all the elements if the window size exceeds the element count.
-TEST(RunningAverageTest, LongWindow) {
-  RunningAverage running_average(arraysize(kTestValues) + 1);
-  EXPECT_EQ(0, running_average.Average());
-
-  for (size_t i = 0; i < arraysize(kTestValues); ++i) {
-    running_average.Record(kTestValues[i]);
-
-    double expected = 0.0;
-    for (size_t j = 0; j <= i; ++j)
-      expected += kTestValues[j];
-    expected /= i + 1;
-
-    EXPECT_EQ(expected, running_average.Average());
-  }
-}
-
-}  // namespace remoting
diff --git a/remoting/base/running_average.cc b/remoting/base/running_samples.cc
index 5e24c0d..d76a1a6 100644
--- a/remoting/base/running_average.cc
+++ b/remoting/base/running_samples.cc
@@ -1,22 +1,23 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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 "remoting/base/running_average.h"
+#include "remoting/base/running_samples.h"
+
+#include <algorithm>
 
 #include "base/logging.h"
 
 namespace remoting {
 
-RunningAverage::RunningAverage(int window_size)
-    : window_size_(window_size),
-      sum_(0) {
+RunningSamples::RunningSamples(int window_size)
+    : window_size_(window_size) {
   DCHECK_GT(window_size, 0);
 }
 
-RunningAverage::~RunningAverage() {}
+RunningSamples::~RunningSamples() {}
 
-void RunningAverage::Record(int64_t value) {
+void RunningSamples::Record(int64_t value) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   data_points_.push_back(value);
@@ -28,7 +29,7 @@ void RunningAverage::Record(int64_t value) {
   }
 }
 
-double RunningAverage::Average() {
+double RunningSamples::Average() const {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   if (data_points_.empty())
@@ -36,4 +37,13 @@ double RunningAverage::Average() {
   return static_cast<double>(sum_) / data_points_.size();
 }
 
+int64_t RunningSamples::Max() const {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (data_points_.empty())
+    return 0;
+
+  return *std::max_element(data_points_.begin(), data_points_.end());
+}
+
 }  // namespace remoting
diff --git a/remoting/base/running_average.h b/remoting/base/running_samples.h
index e41234e..3f5078d 100644
--- a/remoting/base/running_average.h
+++ b/remoting/base/running_samples.h
@@ -1,9 +1,9 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
-#ifndef REMOTING_BASE_RUNNING_AVERAGE_H_
-#define REMOTING_BASE_RUNNING_AVERAGE_H_
+#ifndef REMOTING_BASE_RUNNING_SAMPLES_H_
+#define REMOTING_BASE_RUNNING_SAMPLES_H_
 
 #include <stddef.h>
 #include <stdint.h>
@@ -15,20 +15,26 @@
 
 namespace remoting {
 
-// Calculates the average of the most recent N recorded samples.
+// Calculates the maximum or average of the most recent N recorded samples.
 // This is typically used to smooth out random variation in point samples
 // over bandwidth, frame rate, etc.
-class RunningAverage {
+class RunningSamples {
  public:
-  // Constructs a helper to average over the |window_size| most recent samples.
-  explicit RunningAverage(int window_size);
-  virtual ~RunningAverage();
+  // Constructs a running sample helper that stores |window_size| most
+  // recent samples.
+  explicit RunningSamples(int window_size);
+  virtual ~RunningSamples();
 
   // Records a point sample.
   void Record(int64_t value);
 
   // Returns the average over up to |window_size| of the most recent samples.
-  double Average();
+  // 0 if no sample available
+  double Average() const;
+
+  // Returns the max over up to |window_size| of the most recent samples.
+  // 0 if no sample available
+  int64_t Max() const;
 
  private:
   // Stores the desired window size, as size_t to avoid casting when comparing
@@ -39,13 +45,13 @@ class RunningAverage {
   std::deque<int64_t> data_points_;
 
   // Holds the sum of the samples in |data_points_|.
-  int64_t sum_;
+  int64_t sum_ = 0;
 
   base::ThreadChecker thread_checker_;
 
-  DISALLOW_COPY_AND_ASSIGN(RunningAverage);
+  DISALLOW_COPY_AND_ASSIGN(RunningSamples);
 };
 
 }  // namespace remoting
 
-#endif  // REMOTING_BASE_RUNNING_AVERAGE_H_
+#endif  // REMOTING_BASE_RUNNING_SAMPLES_H_
diff --git a/remoting/base/running_samples_unittest.cc b/remoting/base/running_samples_unittest.cc
new file mode 100644
index 0000000..2c2c7f5
--- /dev/null
+++ b/remoting/base/running_samples_unittest.cc
@@ -0,0 +1,92 @@
+// Copyright 2013 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 <stddef.h>
+#include <stdint.h>
+
+#include "base/macros.h"
+#include "remoting/base/running_samples.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace remoting {
+
+typedef void (*TestFunction)(size_t i, RunningSamples& samples);
+
+static const int64_t kTestValues[] = { 10, 20, 30, 10, 25, 16, 15 };
+
+// Test framework that verifies average() and max() at beginning, iterates
+// through all elements and meanwhile calls your own test function
+static void TestFramework(int windowSize, TestFunction testFn) {
+  RunningSamples samples(windowSize);
+  EXPECT_EQ(0, samples.Average());
+  EXPECT_EQ(0, samples.Max());
+
+  for (size_t i = 0; i < arraysize(kTestValues); ++i) {
+    samples.Record(kTestValues[i]);
+    testFn(i, samples);
+  }
+}
+
+// Average across a single element, i.e. just return the most recent.
+TEST(RunningSamplesTest, AverageOneElementWindow) {
+  TestFramework(1, [](size_t i, RunningSamples& samples) {
+    EXPECT_EQ(static_cast<double>(kTestValues[i]), samples.Average());
+  });
+}
+
+// Average the two most recent elements.
+TEST(RunningSamplesTest, AverageTwoElementWindow) {
+  TestFramework(2, [](size_t i, RunningSamples& samples) {
+    double expected = kTestValues[i];
+    if (i > 0)
+      expected = (expected + kTestValues[i-1]) / 2;
+
+    EXPECT_EQ(expected, samples.Average());
+  });
+}
+
+// Average across all the elements if the window size exceeds the element count.
+TEST(RunningSamplesTest, AverageLongWindow) {
+  TestFramework(arraysize(kTestValues) + 1,
+      [](size_t i, RunningSamples& samples) {
+    double expected = 0.0;
+    for (size_t j = 0; j <= i; ++j)
+      expected += kTestValues[j];
+    expected /= i + 1;
+
+    EXPECT_EQ(expected, samples.Average());
+  });
+}
+
+// Max of a single element, i.e. just return the most recent.
+TEST(RunningSamplesTest, MaxOneElementWindow) {
+  TestFramework(1, [](size_t i, RunningSamples& samples) {
+    EXPECT_EQ(static_cast<double>(kTestValues[i]), samples.Max());
+  });
+}
+
+// Max of the two most recent elements.
+TEST(RunningSamplesTest, MaxTwoElementWindow) {
+  TestFramework(2, [](size_t i, RunningSamples& samples) {
+    double expected = kTestValues[i];
+    if (i > 0)
+      expected = expected > kTestValues[i-1] ? expected : kTestValues[i-1];
+
+    EXPECT_EQ(expected, samples.Max());
+  });
+}
+
+// Max of all the elements if the window size exceeds the element count.
+TEST(RunningSamplesTest, MaxLongWindow) {
+  TestFramework(arraysize(kTestValues) + 1,
+      [](size_t i, RunningSamples& samples) {
+    int64_t expected = -1;
+    for (size_t j = 0; j <= i; ++j)
+      expected = expected > kTestValues[j] ? expected : kTestValues[j];
+
+    EXPECT_EQ(expected, samples.Max());
+  });
+}
+
+}  // namespace remoting
\ No newline at end of file