bug 1312778 - Ensure histogram recording is enabled before remote accumulation r=gfritzsche

There is a mechanism to selectively turn hgram recording off and on. This is
presently only used to throttle an otherwise-devastatingly-chatty hgram to only
contain accumulations from specific times (sync scroll).

This was only checked on the parent. This checks it on the child as well.

MozReview-Commit-ID: 4f0VXMHLaPW

toolkit/components/telemetry/TelemetryHistogram.cpp

@@ -1399,6 +1399,11 @@ internal_RemoteAccumulate(mozilla::Telemetry::ID aId, uint32_t aSample)
   if (XRE_IsParentProcess()) {
     return false;
   }
+  Histogram *h;
+  nsresult rv = internal_GetHistogramByEnumId(aId, &h, GeckoProcessType_Default);
+  if (NS_SUCCEEDED(rv) && !h->IsRecordingEnabled()) {
+    return true;
+  }
   if (!gAccumulations) {
     gAccumulations = new nsTArray<Accumulation>();
   }
@@ -1419,6 +1424,13 @@ internal_RemoteAccumulate(mozilla::Telemetry::ID aId,
   if (XRE_IsParentProcess()) {
     return false;
   }
+  const HistogramInfo& th = gHistograms[aId];
+  KeyedHistogram* keyed
+     = internal_GetKeyedHistogramById(nsDependentCString(th.id()));
+  MOZ_ASSERT(keyed);
+  if (!keyed->IsRecordingEnabled()) {
+    return false;
+  }
   if (!gKeyedAccumulations) {
     gKeyedAccumulations = new nsTArray<KeyedAccumulation>();
   }

toolkit/components/telemetry/tests/unit/test_ChildHistograms.js

@@ -18,6 +18,9 @@ function run_child_test() {
   let flagHist = Telemetry.getHistogramById("TELEMETRY_TEST_FLAG");
   flagHist.add(1);
   let countHist = Telemetry.getHistogramById("TELEMETRY_TEST_COUNT");
+  Telemetry.setHistogramRecordingEnabled("TELEMETRY_TEST_COUNT", false);
+  countHist.add();
+  Telemetry.setHistogramRecordingEnabled("TELEMETRY_TEST_COUNT", true);
   countHist.add();
   countHist.add();
   let categHist = Telemetry.getHistogramById("TELEMETRY_TEST_CATEGORICAL");
@@ -28,6 +31,10 @@ function run_child_test() {
   flagKeyed.add("a", 1);
   flagKeyed.add("b", 1);
   let countKeyed = Telemetry.getKeyedHistogramById("TELEMETRY_TEST_KEYED_COUNT");
+  Telemetry.setHistogramRecordingEnabled("TELEMETRY_TEST_KEYED_COUNT", false);
+  countKeyed.add("a");
+  countKeyed.add("b");
+  Telemetry.setHistogramRecordingEnabled("TELEMETRY_TEST_KEYED_COUNT", true);
   countKeyed.add("a");
   countKeyed.add("b");
   countKeyed.add("b");