Bug 1541819 - Allow tracking memory only for one global or only DevTools ones. r=jdescottes

Differential Revision: https://phabricator.services.mozilla.com/D26104

--HG--
extra : moz-landing-system : lando

devtools/client/shared/test/shared-head.js

@@ -25,7 +25,7 @@ if (DEBUG_ALLOCATIONS) {
   loader.invisibleToDebugger = true;
 
   const { allocationTracker } = loader.require("devtools/shared/test-helpers/allocation-tracker");
-  const tracker = allocationTracker();
+  const tracker = allocationTracker({ watchAllGlobals: true });
   registerCleanupFunction(() => {
     if (DEBUG_ALLOCATIONS == "normal") {
       tracker.logCount();

devtools/shared/test-helpers/allocation-tracker.js

@@ -42,7 +42,18 @@ const global = Cu.getGlobalForObject(this);
 const {addDebuggerToGlobal} = ChromeUtils.import("resource://gre/modules/jsdebugger.jsm");
 addDebuggerToGlobal(global);
 
-exports.allocationTracker = function() {
+/**
+ * Start recording JS object allocations.
+ *
+ * @param Object watchGlobal
+ *        One global object to observe. Only allocation made from this global
+ *        will be recorded.
+ * @param Boolean watchAllGlobals
+ *        If true, allocations from everywhere are going to be recorded.
+ * @param Boolean watchAllGlobals
+ *        If true, only allocations made from DevTools contexts are going to be recorded.
+ */
+exports.allocationTracker = function({ watchGlobal, watchAllGlobals, watchDevToolsGlobals } = {}) {
   dump("DEVTOOLS ALLOCATION: Start logging allocations\n");
   let dbg = new global.Debugger();
 
@@ -53,8 +64,37 @@ exports.allocationTracker = function() {
   // Bumps the default buffer size, which may prevent recording all the test allocations
   dbg.memory.maxAllocationsLogLength = 5000000;
 
+  let acceptGlobal;
+  if (watchGlobal) {
+    acceptGlobal = () => false;
+    dbg.addDebuggee(watchGlobal);
+  } else if (watchAllGlobals) {
+    acceptGlobal = () => true;
+  } else if (watchDevToolsGlobals) {
+    // Only accept globals related to DevTools
+    acceptGlobal = g => {
+      // self-hosting-global crashes when trying to call unsafeDereference
+      if (g.class == "self-hosting-global") {
+        return false;
+      }
+      let ref = g.unsafeDereference();
+      let location = Cu.getRealmLocation(ref);
+      let accept = !!location.match(/devtools/i);
+      dump("NEW GLOBAL: " + (accept ? "+" : "-") + " : " + location + "\n");
+      return accept;
+    };
+  }
+
   // Watch all globals
-  dbg.addAllGlobalsAsDebuggees();
+  if (watchAllGlobals || watchDevToolsGlobals) {
+    dbg.addAllGlobalsAsDebuggees();
+
+    for(let g of dbg.getDebuggees()) {
+      if (!acceptGlobal(g)) {
+        dbg.removeDebuggee(g);
+      }
+    }
+  }
 
   // Remove this global to ignore all its object/JS
   dbg.removeDebuggee(global);
@@ -62,7 +102,9 @@ exports.allocationTracker = function() {
   // addAllGlobalsAsDebuggees won't automatically track new ones,
   // so ensure tracking all new globals
   dbg.onNewGlobalObject = function(g) {
-    dbg.addDebuggee(g);
+    if (acceptGlobal(g)) {
+      dbg.addDebuggee(g);
+    }
   };
 
   return {