Adding UseCounter specific for extensions

third_party/WebKit/Source/core/frame/UseCounterTest.cpp

Index: third_party/WebKit/Source/core/frame/UseCounterTest.cpp
diff --git a/third_party/WebKit/Source/core/frame/UseCounterTest.cpp b/third_party/WebKit/Source/core/frame/UseCounterTest.cpp
index 864057a4d9610261007da901009f175b4acc5d36..030f8bc4f4efea4cfbd071499133d2c973421dc7 100644
--- a/third_party/WebKit/Source/core/frame/UseCounterTest.cpp
+++ b/third_party/WebKit/Source/core/frame/UseCounterTest.cpp
@@ -16,6 +16,8 @@ const char* const kFeaturesHistogramName = "Blink.UseCounter.Features";
 const char* const kCSSHistogramName = "Blink.UseCounter.CSSProperties";
 const char* const kAnimatedCSSHistogramName =
     "Blink.UseCounter.AnimatedCSSProperties";
+const char* const kExtensionFeaturesHistogramName =

[Rick Byers, 2017/04/28 15:04:40]

nit: please add this to the unaffected_histograms list for other tests.  I know
it's getting a little hard to read - maybe we could simplify things by having a
"all_histograms" list that includes everything and verify only the expected ones
change (rather than listed all the unaffected ones for each test?).

+    "Blink.UseCounter.Extensions.Features";
 
 const char* const kSVGFeaturesHistogramName =
     "Blink.UseCounter.SVGImage.Features";
@@ -238,6 +240,23 @@ TEST(UseCounterTest, SVGImageContextAnimatedCSSProperties) {
       1 /* page visit bucket */);
 }
 
+TEST(UseCounterTest, RecordingExtensions) {
+  UseCounter use_counter(UseCounter::kExtensionContext);
+  HistogramBasicTest<UseCounter::Feature>(
+      kExtensionFeaturesHistogramName, kLegacyFeaturesHistogramName,
+      {kSVGFeaturesHistogramName, kFeaturesHistogramName}, UseCounter::kFetch,
+      UseCounter::kFetchBodyStream,
+      [&](UseCounter::Feature feature) -> bool {
+        return use_counter.HasRecordedMeasurement(feature);
+      },
+      [&](UseCounter::Feature feature) {
+        use_counter.RecordMeasurement(feature);
+      },
+      [](UseCounter::Feature feature) -> int { return feature; },
+      [&](KURL kurl) { use_counter.DidCommitLoad(kurl); },
+      "chrome-extension://dummysite", UseCounter::kPageVisits);
+}
+
 // Failing on Android: crbug.com/667913
 #if OS(ANDROID)
 #define MAYBE_InspectorDisablesMeasurement DISABLED_InspectorDisablesMeasurement