diff --git a/devtools/shared/heapsnapshot/HeapAnalysesClient.js b/devtools/shared/heapsnapshot/HeapAnalysesClient.js
index b023bb73d4c9..8182e57cbf88 100644
--- a/devtools/shared/heapsnapshot/HeapAnalysesClient.js
+++ b/devtools/shared/heapsnapshot/HeapAnalysesClient.js
@@ -69,6 +69,9 @@ HeapAnalysesClient.prototype.readHeapSnapshot = function (snapshotFilePath) {
  *          Whether or not the census is returned as a CensusTreeNode,
  *          or just a breakdown report. Defaults to false.
  *          @see `devtools/shared/heapsnapshot/census-tree-node.js`
+ *        - {Boolean} asInvertedTreeNode
+ *          Whether or not the census is returned as an inverted
+ *          CensusTreeNode. Defaults to false.
  *
  * @returns Promise<census report|CensusTreeNode>
  *          The report generated by the given census breakdown, or
@@ -106,6 +109,9 @@ HeapAnalysesClient.prototype.takeCensus = function (snapshotFilePath,
  *        - {Boolean} asTreeNode
  *          Whether the resulting delta report should be converted to a census
  *          tree node before returned. Defaults to false.
+ *        - {Boolean} asInvertedTreeNode
+ *          Whether or not the census is returned as an inverted
+ *          CensusTreeNode. Defaults to false.
  *
  * @returns Promise<delta report|CensusTreeNode>
  *          The delta report generated by diffing the two census reports, or a
diff --git a/devtools/shared/heapsnapshot/HeapAnalysesWorker.js b/devtools/shared/heapsnapshot/HeapAnalysesWorker.js
index 0f613408f86b..aebff40066dc 100644
--- a/devtools/shared/heapsnapshot/HeapAnalysesWorker.js
+++ b/devtools/shared/heapsnapshot/HeapAnalysesWorker.js
@@ -37,9 +37,14 @@ workerHelper.createTask(self, "takeCensus", ({ snapshotFilePath, censusOptions,
   }
 
   let report = snapshots[snapshotFilePath].takeCensus(censusOptions);
-  return requestOptions.asTreeNode
-    ? censusReportToCensusTreeNode(censusOptions.breakdown, report)
-    : report;
+
+  if (requestOptions.asTreeNode) {
+    return censusReportToCensusTreeNode(censusOptions.breakdown, report);
+  } else if (requestOptions.asInvertedTreeNode) {
+    return censusReportToCensusTreeNode(censusOptions.breakdown, report, { invert: true });
+  } else {
+    return report;
+  }
 });
 
 /**
@@ -65,7 +70,11 @@ workerHelper.createTask(self, "takeCensusDiff", request => {
   const second = snapshots[secondSnapshotFilePath].takeCensus(censusOptions);
   const delta = CensusUtils.diff(censusOptions.breakdown, first, second);
 
-  return requestOptions.asTreeNode
-    ? censusReportToCensusTreeNode(censusOptions.breakdown, delta)
-    : delta;
+  if (requestOptions.asTreeNode) {
+    return censusReportToCensusTreeNode(censusOptions.breakdown, delta);
+  } else if (requestOptions.asInvertedTreeNode) {
+    return censusReportToCensusTreeNode(censusOptions.breakdown, delta, { invert: true });
+  } else {
+    return delta;
+  }
 });
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensusDiff_02.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensusDiff_02.js
new file mode 100644
index 000000000000..f676d3273069
--- /dev/null
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensusDiff_02.js
@@ -0,0 +1,54 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Test that the HeapAnalyses{Client,Worker} can take diffs between censuses as
+// inverted trees.
+
+function run_test() {
+  run_next_test();
+}
+
+const BREAKDOWN = {
+  by: "coarseType",
+  objects: {
+    by: "objectClass",
+    then: { by: "count", count: true, bytes: true },
+    other: { by: "count", count: true, bytes: true },
+  },
+  scripts: {
+    by: "internalType",
+    then: { by: "count", count: true, bytes: true },
+  },
+  strings: {
+    by: "internalType",
+    then: { by: "count", count: true, bytes: true },
+  },
+  other: {
+    by: "internalType",
+    then: { by: "count", count: true, bytes: true },
+  },
+};
+
+add_task(function* () {
+  const firstSnapshotFilePath = saveNewHeapSnapshot();
+  const secondSnapshotFilePath = saveNewHeapSnapshot();
+
+  const client = new HeapAnalysesClient();
+  yield client.readHeapSnapshot(firstSnapshotFilePath);
+  yield client.readHeapSnapshot(secondSnapshotFilePath);
+
+  ok(true, "Should have read both heap snapshot files");
+
+  const delta = yield client.takeCensusDiff(firstSnapshotFilePath,
+                                            secondSnapshotFilePath,
+                                            { breakdown: BREAKDOWN });
+
+  const deltaTreeNode = yield client.takeCensusDiff(firstSnapshotFilePath,
+                                                    secondSnapshotFilePath,
+                                                    { breakdown: BREAKDOWN },
+                                                    { asInvertedTreeNode: true });
+
+  compareCensusViewData(BREAKDOWN, delta, deltaTreeNode, { invert: true });
+
+  client.destroy();
+});
diff --git a/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_07.js b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_07.js
new file mode 100644
index 000000000000..6f5c3d184f0d
--- /dev/null
+++ b/devtools/shared/heapsnapshot/tests/unit/test_HeapAnalyses_takeCensus_07.js
@@ -0,0 +1,52 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// Test that the HeapAnalyses{Client,Worker} can take censuses and return
+// an inverted CensusTreeNode.
+
+function run_test() {
+  run_next_test();
+}
+
+const BREAKDOWN = {
+  by: "coarseType",
+  objects: {
+    by: "objectClass",
+    then: { by: "count", count: true, bytes: true },
+    other: { by: "count", count: true, bytes: true },
+  },
+  scripts: {
+    by: "internalType",
+    then: { by: "count", count: true, bytes: true },
+  },
+  strings: {
+    by: "internalType",
+    then: { by: "count", count: true, bytes: true },
+  },
+  other: {
+    by: "internalType",
+    then: { by: "count", count: true, bytes: true },
+  },
+};
+
+add_task(function* () {
+  const client = new HeapAnalysesClient();
+
+  const snapshotFilePath = saveNewHeapSnapshot();
+  yield client.readHeapSnapshot(snapshotFilePath);
+  ok(true, "Should have read the heap snapshot");
+
+  const report = yield client.takeCensus(snapshotFilePath, {
+    breakdown: BREAKDOWN
+  });
+
+  const treeNode = yield client.takeCensus(snapshotFilePath, {
+    breakdown: BREAKDOWN
+  }, {
+    asInvertedTreeNode: true
+  });
+
+  compareCensusViewData(BREAKDOWN, report, treeNode, { invert: true });
+
+  client.destroy();
+});
diff --git a/devtools/shared/heapsnapshot/tests/unit/xpcshell.ini b/devtools/shared/heapsnapshot/tests/unit/xpcshell.ini
index 9614985cf5b4..f81e4817693c 100644
--- a/devtools/shared/heapsnapshot/tests/unit/xpcshell.ini
+++ b/devtools/shared/heapsnapshot/tests/unit/xpcshell.ini
@@ -25,12 +25,14 @@ support-files =
 [test_census-tree-node-07.js]
 [test_HeapAnalyses_readHeapSnapshot_01.js]
 [test_HeapAnalyses_takeCensusDiff_01.js]
+[test_HeapAnalyses_takeCensusDiff_02.js]
 [test_HeapAnalyses_takeCensus_01.js]
 [test_HeapAnalyses_takeCensus_02.js]
 [test_HeapAnalyses_takeCensus_03.js]
 [test_HeapAnalyses_takeCensus_04.js]
 [test_HeapAnalyses_takeCensus_05.js]
 [test_HeapAnalyses_takeCensus_06.js]
+[test_HeapAnalyses_takeCensus_07.js]
 [test_HeapSnapshot_creationTime_01.js]
 [test_HeapSnapshot_takeCensus_01.js]
 [test_HeapSnapshot_takeCensus_02.js]