[Most Visited] Log suggestion provider to UMA

chrome/browser/search/most_visited_iframe_source_unittest.cc

Index: chrome/browser/search/most_visited_iframe_source_unittest.cc
diff --git a/chrome/browser/search/most_visited_iframe_source_unittest.cc b/chrome/browser/search/most_visited_iframe_source_unittest.cc
index 1fbfe19685c2a4aac1b3083246862434d0947fe8..22dd62cd395f3b5a369197407f05cb59cf05009f 100644
--- a/chrome/browser/search/most_visited_iframe_source_unittest.cc
+++ b/chrome/browser/search/most_visited_iframe_source_unittest.cc
@@ -5,6 +5,7 @@
 #include "base/bind.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/statistics_recorder.h"
+#include "base/strings/stringprintf.h"
 #include "chrome/browser/search/most_visited_iframe_source.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -23,7 +24,7 @@ class MostVisitedIframeSourceTest : public testing::Test {
   scoped_ptr<MostVisitedIframeSource> source_;
 };
 
-TEST_F(MostVisitedIframeSourceTest, LogEndpointIsValid) {
+TEST_F(MostVisitedIframeSourceTest, LogEndpointIsValidNoProvider) {
   content::URLDataSource::GotDataCallback callback = base::Bind(
       &MostVisitedIframeSourceTest::ExpectNullData, base::Unretained(this));
 
@@ -63,3 +64,41 @@ TEST_F(MostVisitedIframeSourceTest, LogEndpointIsValid) {
   // Total count hasn't changed.
   EXPECT_EQ(samples2->TotalCount() + 2, samples3->TotalCount());
 }
+
+TEST_F(MostVisitedIframeSourceTest, LogEndpointIsValidWithProvider) {
+  content::URLDataSource::GotDataCallback callback = base::Bind(
+      &MostVisitedIframeSourceTest::ExpectNullData, base::Unretained(this));
+
+  base::StatisticsRecorder::Initialize();
+  // Making sure a test histogram with provider is created by logging a dummy
+  // value.
+  const std::string histogram_name =
+      MostVisitedIframeSource::GetHistogramNameForProvider("foobar");
+  UMA_HISTOGRAM_ENUMERATION(histogram_name, 0,
+                            MostVisitedIframeSource::kNumMostVisited);
+
+  base::HistogramBase* histogram = base::StatisticsRecorder::FindHistogram(
+      histogram_name);
+  scoped_ptr<base::HistogramSamples> samples1(histogram->SnapshotSamples());
+  // The dummy value got logged.
+  EXPECT_EQ(1, samples1->TotalCount());
+  EXPECT_EQ(1, samples1->GetCount(0));
+
+  // Test the method.
+  source()->StartDataRequest("log.html?pos=1&pr=foobar", 0, 0, callback);
+
+  scoped_ptr<base::HistogramSamples> samples2(histogram->SnapshotSamples());
+  EXPECT_EQ(samples1->TotalCount() + 1, samples2->TotalCount());
+  EXPECT_EQ(1, samples2->GetCount(1));
+
+  // Counts accumulate and behave as expected.
+  source()->StartDataRequest("log.html?pos=5&pr=foobar", 0, 0, callback);
+  source()->StartDataRequest("log.html?pos=1&pr=foobar", 0, 0, callback);
+  // This should have no effect for the "foobar" histogram.
+  source()->StartDataRequest("log.html?pos=1&pr=nofoo", 0, 0, callback);
+
+  scoped_ptr<base::HistogramSamples> samples3(histogram->SnapshotSamples());
+  EXPECT_EQ(samples2->TotalCount() + 2, samples3->TotalCount());
+  EXPECT_EQ(1, samples3->GetCount(5));
+  EXPECT_EQ(2, samples3->GetCount(1));
+}