Revert 212378 "Add a HistogramRecorder class and use cases."

trunk/src/net/url_request/url_request_throttler_unittest.cc

Index: trunk/src/net/url_request/url_request_throttler_unittest.cc
===================================================================
--- trunk/src/net/url_request/url_request_throttler_unittest.cc	(revision 212417)
+++ trunk/src/net/url_request/url_request_throttler_unittest.cc	(working copy)
@@ -1,4 +1,3 @@
-
 // Copyright (c) 2012 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.
@@ -6,12 +5,13 @@
 #include "net/url_request/url_request_throttler_manager.h"
 
 #include "base/memory/scoped_ptr.h"
+#include "base/metrics/histogram.h"
 #include "base/metrics/histogram_samples.h"
+#include "base/metrics/statistics_recorder.h"
 #include "base/pickle.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/stringprintf.h"
-#include "base/test/histogram_recorder.h"
 #include "base/time/time.h"
 #include "net/base/load_flags.h"
 #include "net/base/test_completion_callback.h"
@@ -28,7 +28,10 @@
 
 namespace {
 
-const char kRequestThrottledHistogramName[] = "Throttling.RequestThrottled";
+using base::Histogram;
+using base::HistogramBase;
+using base::HistogramSamples;
+using base::StatisticsRecorder;
 
 class MockURLRequestThrottlerEntry : public URLRequestThrottlerEntry {
  public:
@@ -173,17 +176,31 @@
   }
 
   virtual void SetUp();
+  virtual void TearDown();
 
+  // After calling this function, histogram snapshots in |samples_| contain
+  // only the delta caused by the test case currently running.
+  void CalculateHistogramDeltas();
+
   TimeTicks now_;
   MockURLRequestThrottlerManager manager_;  // Dummy object, not used.
   scoped_refptr<MockURLRequestThrottlerEntry> entry_;
 
-  scoped_ptr<base::HistogramRecorder> histogram_recorder_;
+  std::map<std::string, HistogramSamples*> original_samples_;
+  std::map<std::string, HistogramSamples*> samples_;
 
   TestURLRequestContext context_;
   TestURLRequest request_;
 };
 
+// List of all histograms we care about in these unit tests.
+const char* kHistogramNames[] = {
+  "Throttling.FailureCountAtSuccess",
+  "Throttling.PerceivedDowntime",
+  "Throttling.RequestThrottled",
+  "Throttling.SiteOptedOut",
+};
+
 void URLRequestThrottlerEntryTest::SetUp() {
   request_.set_load_flags(0);
 
@@ -191,9 +208,45 @@
   entry_ = new MockURLRequestThrottlerEntry(&manager_);
   entry_->ResetToBlank(now_);
 
-  histogram_recorder_.reset(new base::HistogramRecorder());
+  for (size_t i = 0; i < arraysize(kHistogramNames); ++i) {
+    // Must retrieve original samples for each histogram for comparison
+    // as other tests may affect them.
+    const char* name = kHistogramNames[i];
+    HistogramBase* histogram = StatisticsRecorder::FindHistogram(name);
+    if (histogram) {
+      original_samples_[name] = histogram->SnapshotSamples().release();
+    } else {
+      original_samples_[name] = NULL;
+    }
+  }
 }
 
+void URLRequestThrottlerEntryTest::TearDown() {
+  STLDeleteValues(&original_samples_);
+  STLDeleteValues(&samples_);
+}
+
+void URLRequestThrottlerEntryTest::CalculateHistogramDeltas() {
+  for (size_t i = 0; i < arraysize(kHistogramNames); ++i) {
+    const char* name = kHistogramNames[i];
+    HistogramSamples* original = original_samples_[name];
+
+    HistogramBase* histogram = StatisticsRecorder::FindHistogram(name);
+    if (histogram) {
+      ASSERT_EQ(HistogramBase::kUmaTargetedHistogramFlag, histogram->flags());
+
+      scoped_ptr<HistogramSamples> samples(histogram->SnapshotSamples());
+      if (original)
+        samples->Subtract(*original);
+      samples_[name] = samples.release();
+    }
+  }
+
+  // Ensure we don't accidentally use the originals in our tests.
+  STLDeleteValues(&original_samples_);
+  original_samples_.clear();
+}
+
 std::ostream& operator<<(std::ostream& out, const base::TimeTicks& time) {
   return out << time.ToInternalValue();
 }
@@ -207,11 +260,9 @@
   request_.set_load_flags(LOAD_MAYBE_USER_GESTURE);
   EXPECT_FALSE(entry_->ShouldRejectRequest(request_));
 
-  scoped_ptr<base::HistogramSamples> samples(
-      histogram_recorder_->GetHistogramSamplesSinceCreation(
-          kRequestThrottledHistogramName));
-  ASSERT_EQ(1, samples->GetCount(0));
-  ASSERT_EQ(1, samples->GetCount(1));
+  CalculateHistogramDeltas();
+  ASSERT_EQ(1, samples_["Throttling.RequestThrottled"]->GetCount(0));
+  ASSERT_EQ(1, samples_["Throttling.RequestThrottled"]->GetCount(1));
 }
 
 TEST_F(URLRequestThrottlerEntryTest, InterfaceNotDuringExponentialBackoff) {
@@ -221,11 +272,9 @@
       entry_->fake_time_now_ - TimeDelta::FromMilliseconds(1));
   EXPECT_FALSE(entry_->ShouldRejectRequest(request_));
 
-  scoped_ptr<base::HistogramSamples> samples(
-      histogram_recorder_->GetHistogramSamplesSinceCreation(
-          kRequestThrottledHistogramName));
-  ASSERT_EQ(2, samples->GetCount(0));
-  ASSERT_EQ(0, samples->GetCount(1));
+  CalculateHistogramDeltas();
+  ASSERT_EQ(2, samples_["Throttling.RequestThrottled"]->GetCount(0));
+  ASSERT_EQ(0, samples_["Throttling.RequestThrottled"]->GetCount(1));
 }
 
 TEST_F(URLRequestThrottlerEntryTest, InterfaceUpdateFailure) {