Bug 939137 - part 2 - display memory statistics following each mochitest; r=ted

Landing this on a CLOSED TREE

testing/mochitest/tests/SimpleTest/TestRunner.js

@@ -392,6 +392,22 @@ TestRunner.expectChildProcessCrash = function() {
     TestRunner._expectingProcessCrash = true;
 };
 
+/**
+ * Statistics that we want to retrieve and display after every test is
+ * done.  The keys of this table are intended to be identical to the
+ * relevant attributes of nsIMemoryReporterManager.  However, since
+ * nsIMemoryReporterManager doesn't necessarily support all these
+ * statistics in all build configurations, we also use this table to
+ * tell us whether statistics are supported or not.
+ */
+var MEM_STAT_UNKNOWN = 0;
+var MEM_STAT_UNSUPPORTED = 1;
+var MEM_STAT_SUPPORTED = 2;
+TestRunner._hasMemoryStatistics = {}
+TestRunner._hasMemoryStatistics.vsize = MEM_STAT_UNKNOWN;
+TestRunner._hasMemoryStatistics.heapAllocated = MEM_STAT_UNKNOWN;
+TestRunner._hasMemoryStatistics.largestContiguousVMBlock = MEM_STAT_UNKNOWN;
+
 /**
  * This stub is called by SimpleTest when a test is finished.
 **/
@@ -409,6 +425,28 @@ TestRunner.testFinished = function(tests) {
     TestRunner._lastTestFinished = TestRunner._currentTest;
     TestRunner._loopIsRestarting = false;
 
+    var mrm = SpecialPowers.Cc["@mozilla.org/memory-reporter-manager;1"]
+                           .getService(SpecialPowers.Ci.nsIMemoryReporterManager);
+    for (stat in TestRunner._hasMemoryStatistics) {
+        var supported = TestRunner._hasMemoryStatistics[stat];
+        var firstAccess = false;
+        if (supported == MEM_STAT_UNKNOWN) {
+            firstAccess = true;
+            try {
+                var value = mrm[stat];
+                supported = MEM_STAT_SUPPORTED;
+            } catch (e) {
+                supported = MEM_STAT_UNSUPPORTED;
+            }
+            TestRunner._hasMemoryStatistics[stat] = supported;
+        }
+        if (supported == MEM_STAT_SUPPORTED) {
+            TestRunner.log("TEST-INFO | MEMORY STAT " + stat + " after test: " + mrm[stat]);
+        } else if (firstAccess) {
+            TestRunner.log("TEST-INFO | MEMORY STAT " + stat + " not supported in this build configuration.");
+        }
+    }
+
     function cleanUpCrashDumpFiles() {
         if (!SpecialPowers.removeExpectedCrashDumpFiles(TestRunner._expectingProcessCrash)) {
             TestRunner.error("TEST-UNEXPECTED-FAIL | " +