Add BytesRead metric to CPM

chrome/browser/performance_monitor/performance_monitor_browsertest.cc

Index: chrome/browser/performance_monitor/performance_monitor_browsertest.cc
diff --git a/chrome/browser/performance_monitor/performance_monitor_browsertest.cc b/chrome/browser/performance_monitor/performance_monitor_browsertest.cc
index 3d0234cefc8b4a2a30da6a4eeef673fdc17a1c35..663186db90f93d09cd680d7cfe16ae1a94dbe6a1 100644
--- a/chrome/browser/performance_monitor/performance_monitor_browsertest.cc
+++ b/chrome/browser/performance_monitor/performance_monitor_browsertest.cc
@@ -159,6 +159,10 @@ class PerformanceMonitorBrowserTest : public ExtensionBrowserTest {
     performance_monitor_->Start();
 
     windowed_observer.Wait();
+
+    // We stop the timer in charge of doing timed collections so that we can
+    // enforce when, and how many times, we do these collections.
+    performance_monitor_->timer_.Stop();
   }
 
   // A handle for gathering statistics from the database, which must be done on
@@ -721,4 +725,36 @@ IN_PROC_BROWSER_TEST_F(PerformanceMonitorBrowserTest, PageLoadTime) {
   ASSERT_LT(metrics[1].value, kMaxLoadTime.ToInternalValue());
 }
 
+IN_PROC_BROWSER_TEST_F(PerformanceMonitorBrowserTest, BytesRead) {
+  FilePath test_dir;
+  PathService::Get(chrome::DIR_TEST_DATA, &test_dir);
+
+  int64 page1_size = 0;
+  file_util::GetFileSize(test_dir.AppendASCII("title1.html"), &page1_size);
+
+  int64 page2_size = 0;
+  file_util::GetFileSize(test_dir.AppendASCII("title2.html"), &page2_size);
+
+  ui_test_utils::NavigateToURL(
+      browser(),
+      ui_test_utils::GetTestUrl(FilePath(FilePath::kCurrentDirectory),
+                                FilePath(FILE_PATH_LITERAL("title1.html"))));
+  performance_monitor()->DoTimedCollections();
+
+  Database::MetricInfoVector metrics = GetStats(METRIC_BYTES_READ);
+  ASSERT_EQ(1u, metrics.size());
+  ASSERT_EQ(page1_size, metrics[0].value);
+
+  ui_test_utils::NavigateToURL(
+      browser(),
+      ui_test_utils::GetTestUrl(FilePath(FilePath::kCurrentDirectory),
+                                FilePath(FILE_PATH_LITERAL("title2.html"))));
+  performance_monitor()->DoTimedCollections();
+
+  metrics = GetStats(METRIC_BYTES_READ);
+
+  ASSERT_EQ(2u, metrics.size());
+  ASSERT_EQ(page1_size + page2_size, metrics[1].value);
+}
+
 }  // namespace performance_monitor