diff --git a/addon-sdk/source/test/addons/private-browsing-supported/test-windows.js b/addon-sdk/source/test/addons/private-browsing-supported/test-windows.js
index 0c7fba36e2ab..cd638a13c850 100644
--- a/addon-sdk/source/test/addons/private-browsing-supported/test-windows.js
+++ b/addon-sdk/source/test/addons/private-browsing-supported/test-windows.js
@@ -94,7 +94,7 @@ exports.testSettingActiveWindowDoesNotIgnorePrivateWindow = function(assert, don
     // PWPB case
     if (isWindowPBSupported) {
       assert.ok(isPrivate(window), "window is private");
-      assert.notStrictEqual(winUtils.activeBrowserWindow, browserWindow);
+      assert.notDeepEqual(winUtils.activeBrowserWindow, browserWindow);
     }
     // Global case
     else {
@@ -131,19 +131,19 @@ exports.testSettingActiveWindowDoesNotIgnorePrivateWindow = function(assert, don
         continueAfterFocus(winUtils.activeWindow = window);
       },
       function() {
-        assert.strictEqual(winUtils.activeBrowserWindow, window,
-                          "Correct active browser window [3]");
-        assert.strictEqual(winUtils.activeWindow, window,
-                          "Correct active window [3]");
+        assert.deepEqual(winUtils.activeBrowserWindow, window,
+                         "Correct active browser window [3]");
+        assert.deepEqual(winUtils.activeWindow, window,
+                         "Correct active window [3]");
 
         // just to get back to original state
         continueAfterFocus(winUtils.activeWindow = browserWindow);
       },
       function() {
-        assert.strictEqual(winUtils.activeBrowserWindow, browserWindow,
-                          "Correct active browser window when pb mode is supported [4]");
-        assert.strictEqual(winUtils.activeWindow, browserWindow,
-                          "Correct active window when pb mode is supported [4]");
+        assert.deepEqual(winUtils.activeBrowserWindow, browserWindow,
+                         "Correct active browser window when pb mode is supported [4]");
+        assert.deepEqual(winUtils.activeWindow, browserWindow,
+                         "Correct active window when pb mode is supported [4]");
 
         close(window).then(done).then(null, assert.fail);
       }
diff --git a/addon-sdk/source/test/test-window-utils-private-browsing.js b/addon-sdk/source/test/test-window-utils-private-browsing.js
index cf57b19f3c9c..e551687ea96c 100644
--- a/addon-sdk/source/test/test-window-utils-private-browsing.js
+++ b/addon-sdk/source/test/test-window-utils-private-browsing.js
@@ -95,7 +95,7 @@ exports.testSettingActiveWindowDoesNotIgnorePrivateWindow = function(assert, don
     // PWPB case
     if (isWindowPBSupported) {
       assert.ok(isPrivate(window), "window is private");
-      assert.notStrictEqual(windowUtils.activeBrowserWindow, browserWindow);
+      assert.notDeepEqual(windowUtils.activeBrowserWindow, browserWindow);
     }
     // Global case
     else {
@@ -127,18 +127,18 @@ exports.testSettingActiveWindowDoesNotIgnorePrivateWindow = function(assert, don
       // test setting a private window
       return onFocus(windowUtils.activeWindow = window);
     }).then(function() {
-      assert.strictEqual(windowUtils.activeBrowserWindow, window,
-                         "Correct active browser window [3]");
-      assert.strictEqual(windowUtils.activeWindow, window,
-                         "Correct active window [3]");
+      assert.deepEqual(windowUtils.activeBrowserWindow, window,
+                       "Correct active browser window [3]");
+      assert.deepEqual(windowUtils.activeWindow, window,
+                       "Correct active window [3]");
 
       // just to get back to original state
       return onFocus(windowUtils.activeWindow = browserWindow);
     }).then(_ => {
-      assert.strictEqual(windowUtils.activeBrowserWindow, browserWindow,
-                         "Correct active browser window when pb mode is supported [4]");
-      assert.strictEqual(windowUtils.activeWindow, browserWindow,
-                         "Correct active window when pb mode is supported [4]");
+      assert.deepEqual(windowUtils.activeBrowserWindow, browserWindow,
+                       "Correct active browser window when pb mode is supported [4]");
+      assert.deepEqual(windowUtils.activeWindow, browserWindow,
+                       "Correct active window when pb mode is supported [4]");
 
       return close(window);
     })
diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index f4b7f854a5f7..64ab6541ce54 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -8430,7 +8430,7 @@ nsGlobalWindow::ReallyCloseWindow()
 void
 nsGlobalWindow::EnterModalState()
 {
-  MOZ_ASSERT(IsOuterWindow(), "Modal state is maintained on outer windows");
+  FORWARD_TO_OUTER_VOID(EnterModalState, ());
 
   // GetScriptableTop, not GetTop, so that EnterModalState works properly with
   // <iframe mozbrowser>.
@@ -8563,7 +8563,7 @@ private:
 void
 nsGlobalWindow::LeaveModalState()
 {
-  MOZ_ASSERT(IsOuterWindow(), "Modal state is maintained on outer windows");
+  FORWARD_TO_OUTER_VOID(LeaveModalState, ());
 
   nsGlobalWindow* topWin = GetScriptableTop();
 
diff --git a/dom/bindings/BindingUtils.cpp b/dom/bindings/BindingUtils.cpp
index 6a060e8bf6e5..0d4cc79d29ea 100644
--- a/dom/bindings/BindingUtils.cpp
+++ b/dom/bindings/BindingUtils.cpp
@@ -2258,13 +2258,7 @@ GenericBindingGetter(JSContext* cx, unsigned argc, JS::Value* vp)
 
   MOZ_ASSERT(info->type() == JSJitInfo::Getter);
   JSJitGetterOp getter = info->getter;
-  bool ok = getter(cx, obj, self, JSJitGetterCallArgs(args));
-#ifdef DEBUG
-  if (ok) {
-    AssertReturnTypeMatchesJitinfo(info, args.rval());
-  }
-#endif
-  return ok;
+  return getter(cx, obj, self, JSJitGetterCallArgs(args));
 }
 
 bool
@@ -2297,10 +2291,7 @@ GenericBindingSetter(JSContext* cx, unsigned argc, JS::Value* vp)
   if (!setter(cx, obj, self, JSJitSetterCallArgs(args))) {
     return false;
   }
-  args.rval().setUndefined();
-#ifdef DEBUG
-  AssertReturnTypeMatchesJitinfo(info, args.rval());
-#endif
+  args.rval().set(JSVAL_VOID);
   return true;
 }
 
@@ -2328,13 +2319,7 @@ GenericBindingMethod(JSContext* cx, unsigned argc, JS::Value* vp)
   }
   MOZ_ASSERT(info->type() == JSJitInfo::Method);
   JSJitMethodOp method = info->method;
-  bool ok = method(cx, obj, self, JSJitMethodCallArgs(args));
-#ifdef DEBUG
-  if (ok) {
-    AssertReturnTypeMatchesJitinfo(info, args.rval());
-  }
-#endif
-  return ok;
+  return method(cx, obj, self, JSJitMethodCallArgs(args));
 }
 
 bool
@@ -2372,14 +2357,9 @@ GenericPromiseReturningBindingMethod(JSContext* cx, unsigned argc, JS::Value* vp
   JSJitMethodOp method = info->method;
   bool ok = method(cx, obj, self, JSJitMethodCallArgs(args));
   if (ok) {
-#ifdef DEBUG
-    AssertReturnTypeMatchesJitinfo(info, args.rval());
-#endif
     return true;
   }
 
-  // Promise-returning methods always return objects
-  MOZ_ASSERT(info->returnType() == JSVAL_TYPE_OBJECT);
   return ConvertExceptionToPromise(cx, xpc::XrayAwareCalleeGlobal(callee),
                                    args.rval());
 }
@@ -2449,44 +2429,5 @@ CreateGlobalOptions<nsGlobalWindow>::PostCreateGlobal(JSContext* aCx,
   return XPCWrappedNativeScope::GetNewOrUsed(aCx, aGlobal);
 }
 
-#ifdef DEBUG
-void
-AssertReturnTypeMatchesJitinfo(const JSJitInfo* aJitInfo,
-                               JS::Handle<JS::Value> aValue)
-{
-  switch (aJitInfo->returnType()) {
-  case JSVAL_TYPE_UNKNOWN:
-    // Any value is good.
-    break;
-  case JSVAL_TYPE_DOUBLE:
-    // The value could actually be an int32 value as well.
-    MOZ_ASSERT(aValue.isNumber());
-    break;
-  case JSVAL_TYPE_INT32:
-    MOZ_ASSERT(aValue.isInt32());
-    break;
-  case JSVAL_TYPE_UNDEFINED:
-    MOZ_ASSERT(aValue.isUndefined());
-    break;
-  case JSVAL_TYPE_BOOLEAN:
-    MOZ_ASSERT(aValue.isBoolean());
-    break;
-  case JSVAL_TYPE_STRING:
-    MOZ_ASSERT(aValue.isString());
-    break;
-  case JSVAL_TYPE_NULL:
-    MOZ_ASSERT(aValue.isNull());
-    break;
-  case JSVAL_TYPE_OBJECT:
-    MOZ_ASSERT(aValue.isObject());
-    break;
-  default:
-    // Someone messed up their jitinfo type.
-    MOZ_ASSERT(false, "Unexpected JSValueType stored in jitinfo");
-    break;
-  }
-}
-#endif
-
 } // namespace dom
 } // namespace mozilla
diff --git a/dom/bindings/BindingUtils.h b/dom/bindings/BindingUtils.h
index 71bdb7ac1bb7..9d3f98552a56 100644
--- a/dom/bindings/BindingUtils.h
+++ b/dom/bindings/BindingUtils.h
@@ -2744,12 +2744,6 @@ GlobalPropertiesAreOwn()
   return true;
 }
 
-#ifdef DEBUG
-void
-AssertReturnTypeMatchesJitinfo(const JSJitInfo* aJitinfo,
-                               JS::Handle<JS::Value> aValue);
-#endif
-
 } // namespace dom
 } // namespace mozilla
 
diff --git a/dom/bindings/Codegen.py b/dom/bindings/Codegen.py
index 1d7838829d0b..3270a98610e5 100644
--- a/dom/bindings/Codegen.py
+++ b/dom/bindings/Codegen.py
@@ -70,7 +70,7 @@ def indent(s, indentLevel=2):
     Indent C++ code.
 
     Weird secret feature: this doesn't indent lines that start with # (such as
-    #include lines or #ifdef/#endif).
+    #include lines).
     """
     if s == "":
         return s
@@ -6683,13 +6683,7 @@ class CGGenericMethod(CGAbstractBindingMethod):
             const JSJitInfo *info = FUNCTION_VALUE_TO_JITINFO(args.calleev());
             MOZ_ASSERT(info->type() == JSJitInfo::Method);
             JSJitMethodOp method = info->method;
-            bool ok = method(cx, obj, self, JSJitMethodCallArgs(args));
-            #ifdef DEBUG
-            if (ok) {
-              AssertReturnTypeMatchesJitinfo(info, args.rval());
-            }
-            #endif
-            return ok;
+            return method(cx, obj, self, JSJitMethodCallArgs(args));
             """)))
 
 
@@ -6987,13 +6981,7 @@ class CGGenericGetter(CGAbstractBindingMethod):
             const JSJitInfo *info = FUNCTION_VALUE_TO_JITINFO(args.calleev());
             MOZ_ASSERT(info->type() == JSJitInfo::Getter);
             JSJitGetterOp getter = info->getter;
-            bool ok = getter(cx, obj, self, JSJitGetterCallArgs(args));
-            #ifdef DEBUG
-            if (ok) {
-              AssertReturnTypeMatchesJitinfo(info, args.rval());
-            }
-            #endif
-            return ok;
+            return getter(cx, obj, self, JSJitGetterCallArgs(args));
             """)))
 
 
@@ -7128,9 +7116,6 @@ class CGGenericSetter(CGAbstractBindingMethod):
               return false;
             }
             args.rval().set(JSVAL_VOID);
-            #ifdef DEBUG
-            AssertReturnTypeMatchesJitinfo(info, args.rval());
-            #endif
             return true;
             """,
             name=self.descriptor.interface.identifier.name)))
diff --git a/embedding/components/windowwatcher/src/nsAutoWindowStateHelper.cpp b/embedding/components/windowwatcher/src/nsAutoWindowStateHelper.cpp
index 552ea78f5bc2..7b00e8149f6a 100644
--- a/embedding/components/windowwatcher/src/nsAutoWindowStateHelper.cpp
+++ b/embedding/components/windowwatcher/src/nsAutoWindowStateHelper.cpp
@@ -19,19 +19,23 @@ using namespace mozilla::dom;
  ****************** nsAutoWindowStateHelper *********************
  ****************************************************************/
 
-nsAutoWindowStateHelper::nsAutoWindowStateHelper(nsPIDOMWindow *aWindow)
+nsAutoWindowStateHelper::nsAutoWindowStateHelper(nsIDOMWindow *aWindow)
   : mWindow(aWindow),
     mDefaultEnabled(DispatchEventToChrome("DOMWillOpenModalDialog"))
 {
-  if (mWindow) {
-    mWindow->EnterModalState();
+  nsCOMPtr<nsPIDOMWindow> window(do_QueryInterface(aWindow));
+
+  if (window) {
+    window->EnterModalState();
   }
 }
 
 nsAutoWindowStateHelper::~nsAutoWindowStateHelper()
 {
-  if (mWindow) {
-    mWindow->LeaveModalState();
+  nsCOMPtr<nsPIDOMWindow> window(do_QueryInterface(mWindow));
+
+  if (window) {
+    window->LeaveModalState();
   }
 
   if (mDefaultEnabled) {
@@ -42,15 +46,14 @@ nsAutoWindowStateHelper::~nsAutoWindowStateHelper()
 bool
 nsAutoWindowStateHelper::DispatchEventToChrome(const char *aEventName)
 {
-  // XXXbz should we skip dispatching the event if the inner changed?
-  // That is, should we store both the inner and the outer?
-  if (!mWindow) {
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(mWindow);
+  if (!window || (window->IsInnerWindow() && !window->IsCurrentInnerWindow())) {
     return true;
   }
 
   // The functions of nsContentUtils do not provide the required behavior,
   // so the following is inlined.
-  nsIDocument* doc = mWindow->GetExtantDoc();
+  nsIDocument* doc = window->GetExtantDoc();
   if (!doc) {
     return true;
   }
@@ -64,7 +67,7 @@ nsAutoWindowStateHelper::DispatchEventToChrome(const char *aEventName)
   event->SetTrusted(true);
   event->GetInternalNSEvent()->mFlags.mOnlyChromeDispatch = true;
 
-  nsCOMPtr<EventTarget> target = do_QueryInterface(mWindow);
+  nsCOMPtr<EventTarget> target = do_QueryInterface(window);
   bool defaultActionEnabled;
   target->DispatchEvent(event, &defaultActionEnabled);
   return defaultActionEnabled;
diff --git a/embedding/components/windowwatcher/src/nsAutoWindowStateHelper.h b/embedding/components/windowwatcher/src/nsAutoWindowStateHelper.h
index cde50dee7bd1..e23097519b5b 100644
--- a/embedding/components/windowwatcher/src/nsAutoWindowStateHelper.h
+++ b/embedding/components/windowwatcher/src/nsAutoWindowStateHelper.h
@@ -7,19 +7,18 @@
 #define __nsAutoWindowStateHelper_h
 
 #include "nsCOMPtr.h"
-#include "nsPIDOMWindow.h"
 
 /**
  * Helper class for dealing with notifications around opening modal
  * windows.
  */
 
-class nsPIDOMWindow;
+class nsIDOMWindow;
 
 class nsAutoWindowStateHelper
 {
 public:
-  nsAutoWindowStateHelper(nsPIDOMWindow *aWindow);
+  nsAutoWindowStateHelper(nsIDOMWindow *aWindow);
   ~nsAutoWindowStateHelper();
 
   bool DefaultEnabled()
@@ -30,7 +29,7 @@ public:
 protected:
   bool DispatchEventToChrome(const char *aEventName);
 
-  nsCOMPtr<nsPIDOMWindow> mWindow;
+  nsIDOMWindow *mWindow;
   bool mDefaultEnabled;
 };
 
diff --git a/embedding/components/windowwatcher/src/nsWindowWatcher.cpp b/embedding/components/windowwatcher/src/nsWindowWatcher.cpp
index f4b4db0e63e3..67eb3cf2f429 100644
--- a/embedding/components/windowwatcher/src/nsWindowWatcher.cpp
+++ b/embedding/components/windowwatcher/src/nsWindowWatcher.cpp
@@ -955,10 +955,7 @@ nsWindowWatcher::OpenWindowInternal(nsIDOMWindow *aParent,
     // we're opening a modal content window (the helper classes are
     // no-ops if given no window), for chrome dialogs we don't want to
     // do any of that (it's done elsewhere for us).
-    // Make sure we maintain the state on an outer window, because
-    // that's where it lives; inner windows assert if you try to
-    // maintain the state on them.
-    nsAutoWindowStateHelper windowStateHelper(parentWindow->GetOuterWindow());
+    nsAutoWindowStateHelper windowStateHelper(aParent);
 
     if (!windowStateHelper.DefaultEnabled()) {
       // Default to cancel not opening the modal window.
diff --git a/layout/style/nsStyleUtil.cpp b/layout/style/nsStyleUtil.cpp
index 74dac0f1ae93..6f6ceeccd653 100644
--- a/layout/style/nsStyleUtil.cpp
+++ b/layout/style/nsStyleUtil.cpp
@@ -81,16 +81,13 @@ void nsStyleUtil::AppendEscapedCSSString(const nsAString& aString,
 nsStyleUtil::AppendEscapedCSSIdent(const nsAString& aIdent, nsAString& aReturn)
 {
   // The relevant parts of the CSS grammar are:
-  //   ident    ([-]?{nmstart}|[-][-]){nmchar}*
+  //   ident    [-]?{nmstart}{nmchar}*
   //   nmstart  [_a-z]|{nonascii}|{escape}
   //   nmchar   [_a-z0-9-]|{nonascii}|{escape}
   //   nonascii [^\0-\177]
   //   escape   {unicode}|\\[^\n\r\f0-9a-f]
   //   unicode  \\[0-9a-f]{1,6}(\r\n|[ \n\r\t\f])?
-  // from http://www.w3.org/TR/CSS21/syndata.html#tokenization but
-  // modified for idents by
-  // http://dev.w3.org/csswg/cssom/#serialize-an-identifier and
-  // http://dev.w3.org/csswg/css-syntax/#would-start-an-identifier
+  // from http://www.w3.org/TR/CSS21/syndata.html#tokenization
 
   const char16_t* in = aIdent.BeginReading();
   const char16_t* const end = aIdent.EndReading();
@@ -100,13 +97,7 @@ nsStyleUtil::AppendEscapedCSSIdent(const nsAString& aIdent, nsAString& aReturn)
 
   // A leading dash does not need to be escaped as long as it is not the
   // *only* character in the identifier.
-  if (*in == '-') {
-    if (in + 1 == end) {
-      aReturn.Append(char16_t('\\'));
-      aReturn.Append(char16_t('-'));
-      return true;
-    }
-
+  if (in + 1 != end && *in == '-') {
     aReturn.Append(char16_t('-'));
     ++in;
   }
@@ -114,8 +105,16 @@ nsStyleUtil::AppendEscapedCSSIdent(const nsAString& aIdent, nsAString& aReturn)
   // Escape a digit at the start (including after a dash),
   // numerically.  If we didn't escape it numerically, it would get
   // interpreted as a numeric escape for the wrong character.
-  if (in != end && ('0' <= *in && *in <= '9')) {
-    aReturn.AppendPrintf("\\%hX ", *in);
+  // A second dash immediately after a leading dash must also be
+  // escaped, but this may be done symbolically.
+  if (in != end && (*in == '-' ||
+                    ('0' <= *in && *in <= '9'))) {
+    if (*in == '-') {
+      aReturn.Append(char16_t('\\'));
+      aReturn.Append(char16_t('-'));
+    } else {
+      aReturn.AppendPrintf("\\%hX ", *in);
+    }
     ++in;
   }
 
diff --git a/layout/style/test/test_css_escape_api.html b/layout/style/test/test_css_escape_api.html
index 852c00a3b91a..d262df09500f 100644
--- a/layout/style/test/test_css_escape_api.html
+++ b/layout/style/test/test_css_escape_api.html
@@ -66,7 +66,7 @@ is(CSS.escape('-7a'), '-\\37 a', "escapingFailed Char: -7a");
 is(CSS.escape('-8a'), '-\\38 a', "escapingFailed Char: -8a");
 is(CSS.escape('-9a'), '-\\39 a', "escapingFailed Char: -9a");
 
-is(CSS.escape('--a'), '--a', 'Should not need to escape leading "--"');
+is(CSS.escape('--a'), '-\\-a', "escapingFailed Char: --a");
 
 is(CSS.escape('\x80\x2D\x5F\xA9'), '\\80 \x2D\x5F\xA9', "escapingFailed Char: \\x80\\x2D\\x5F\\xA9");
 is(CSS.escape('\xA0\xA1\xA2'), '\xA0\xA1\xA2', "escapingFailed Char: \\xA0\\xA1\\xA2");
diff --git a/layout/style/test/test_parser_diagnostics_unprintables.html b/layout/style/test/test_parser_diagnostics_unprintables.html
index e59989e94c09..e532c2f49bf8 100644
--- a/layout/style/test/test_parser_diagnostics_unprintables.html
+++ b/layout/style/test/test_parser_diagnostics_unprintables.html
@@ -74,7 +74,7 @@ const substitutions = [
   { t: "\\37 ",  i: "\\37 ",  s: "7"  },
   { t: "\\38 ",  i: "\\38 ",  s: "8"  },
   { t: "\\39 ",  i: "\\39 ",  s: "9"  },
-  { t: "-\\-",   i: "--",     s: "--" },
+  { t: "-\\-",   i: "-\\-",   s: "--" },
   { t: "-\\30 ", i: "-\\30 ", s: "-0" },
   { t: "-\\31 ", i: "-\\31 ", s: "-1" },
   { t: "-\\32 ", i: "-\\32 ", s: "-2" },