Add HistogramTester::GetAllSamples.

base/test/histogram_tester.h

 // Copyright 2014 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 BASE_TEST_HISTOGRAM_TESTER_H_
 #define BASE_TEST_HISTOGRAM_TESTER_H_
 
 #include <map>
 #include <string>
+#include <utility>
+#include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/histogram_base.h"
 
 namespace base {
 
 class HistogramSamples;
 
@@ skipping 20 matching lines @@
   void ExpectBucketCount(const std::string& name,
                          base::HistogramBase::Sample sample,
                          base::HistogramBase::Count expected_count) const;
 
   // We don't know the values of the samples, but we know how many there are.
   // This measures the diff from the snapshot taken when this object was
   // constructed.
   void ExpectTotalCount(const std::string& name,
                         base::HistogramBase::Count count) const;
 
+  // Returns a list of all of the buckets recorded since creation of this
+  // object, as pair<Sample, Count>, where the Sample is the min boundary of the
+  // bucket and the Count is the count recorded since creation.

[ncarter (slow), 2015/06/24 17:28:44]

This comment should have code showing the example usage, including the
EXPECT_THAT() and the testing::ElementsAre. Even when I'm looking at the gmock
docs, it's pretty mystifying to figure out how to get these to work from first
principles.

[twifkak, 2015/06/25 20:21:38]

Done.

+  std::vector<std::pair<HistogramBase::Sample, HistogramBase::Count>>
+  GetAllSamples(const std::string& name);
+
   // Access a modified HistogramSamples containing only what has been logged
   // to the histogram since the creation of this object.
   scoped_ptr<HistogramSamples> GetHistogramSamplesSinceCreation(
       const std::string& histogram_name);
 
  private:
   // Verifies and asserts that value in the |sample| bucket matches the
   // |expected_count|. The bucket's current value is determined from |samples|
   // and is modified based on the snapshot stored for histogram |name|.
   void CheckBucketCount(const std::string& name,
@@ skipping 12 matching lines @@
   // lifecycle. This instance takes ownership of the samples, which are deleted
   // when the instance is destroyed.
   std::map<std::string, HistogramSamples*> histograms_snapshot_;
 
   DISALLOW_COPY_AND_ASSIGN(HistogramTester);
 };
 
 }  // namespace base
 
 #endif  // BASE_TEST_HISTOGRAM_TESTER_H_