Bug 1032880 - Disable 'transparent content with displayports' warning in tests. r=tn

--HG--
extra : rebase_source : 21ea67d322cb4a780b67584be4047f6ca8ac6690

layout/base/nsDisplayList.cpp

@@ -65,6 +65,20 @@ using namespace mozilla::dom;
 using namespace mozilla::layout;
 typedef FrameMetrics::ViewID ViewID;
 
+static bool
+SpammyLayoutWarningsEnabled()
+{
+  static bool sValue = false;
+  static bool sValueInitialized = false;
+
+  if (!sValueInitialized) {
+    Preferences::GetBool("layout.spammy_warnings.enabled", &sValue);
+    sValueInitialized = true;
+  }
+
+  return sValue;
+}
+
 static inline nsIFrame*
 GetTransformRootFrame(nsIFrame* aFrame)
 {
@@ -1267,11 +1281,17 @@ void nsDisplayList::PaintForFrame(nsDisplayListBuilder* aBuilder,
                      aBuilder->FindReferenceFrameFor(aForFrame),
                      root, viewport,
                      !isRoot, isRoot, containerParameters);
+
+  // NS_WARNING is debug-only, so don't even bother checking the conditions in
+  // a release build.
+#ifdef DEBUG
   if (usingDisplayport &&
-      !(root->GetContentFlags() & Layer::CONTENT_OPAQUE)) {
+      !(root->GetContentFlags() & Layer::CONTENT_OPAQUE) &&
+      SpammyLayoutWarningsEnabled()) {
     // See bug 693938, attachment 567017
     NS_WARNING("Transparent content with displayports can be expensive.");
   }
+#endif
 
   layerManager->SetRoot(root);
   layerBuilder->WillEndTransaction();

modules/libpref/src/init/all.js

@@ -2046,6 +2046,9 @@ pref("layout.display-list.dump", false);
 // heavily loaded.
 pref("layout.frame_rate.precise", false);
 
+// pref to control whether layout warnings that are hit quite often are enabled 
+pref("layout.spammy_warnings.enabled", true);
+
 // Is support for the Web Animations API enabled?
 #ifdef RELEASE_BUILD
 pref("dom.animations-api.core.enabled", false);

testing/profiles/prefs_general.js

@@ -139,6 +139,9 @@ user_pref("layout.css.grid.enabled", true);
 // Enable CSS Ruby for testing
 user_pref("layout.css.ruby.enabled", true);
 
+// Disable spammy layout warnings because they pollute test logs
+user_pref("layout.spammy_warnings.enabled", false);
+
 // Enable mozContacts
 user_pref("dom.mozContacts.enabled", true);
 user_pref("dom.navigator-property.disable.mozContacts", false);