--- a/accessible/base/StyleInfo.h
+++ b/accessible/base/StyleInfo.h
@@ -6,16 +6,19 @@
 
 #ifndef _mozilla_a11y_style_h_
 #define _mozilla_a11y_style_h_
 
 #include "mozilla/gfx/Types.h"
 #include "mozilla/ComputedStyle.h"
 
 namespace mozilla {
+namespace dom {
+class Element;
+} // namespace dom
 namespace a11y {
 
 class StyleInfo
 {
 public:
   explicit StyleInfo(dom::Element* aElement);
   ~StyleInfo() { }
 

--- a/layout/style/ComputedStyle.h
+++ b/layout/style/ComputedStyle.h
@@ -6,23 +6,26 @@
 
 /* the interface (to internal code) for retrieving computed style data */
 
 #ifndef _ComputedStyle_h_
 #define _ComputedStyle_h_
 
 #include "nsIMemoryReporter.h"
 #include <algorithm>
+#include "mozilla/ArenaObjectID.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/RestyleLogging.h"
 #include "mozilla/ServoStyleSet.h"
+#include "mozilla/ServoTypes.h"
 #include "mozilla/ServoUtils.h"
 #include "mozilla/StyleComplexColor.h"
 #include "mozilla/CachedInheritingStyles.h"
 #include "nsCSSAnonBoxes.h"
+#include "nsCSSPseudoElements.h"
 
 // Includes nsStyleStructID.
 #include "nsStyleStructFwd.h"
 
 // Bits for each struct.
 // NS_STYLE_INHERIT_BIT defined in nsStyleStructFwd.h
 #define NS_STYLE_INHERIT_MASK              0x000ffffff
 
@@ -61,30 +64,36 @@
 // See ComputedStyle::IsTextCombined
 #define NS_STYLE_IS_TEXT_COMBINED          0x800000000
 // Whether a ComputedStyle is a Gecko or Servo context
 #define NS_STYLE_CONTEXT_IS_GECKO          0x1000000000
 // See ComputedStyle::GetPseudoEnum
 #define NS_STYLE_CONTEXT_TYPE_SHIFT        37
 
 class nsAtom;
+enum nsChangeHint : uint32_t;
+class nsIPresShell;
 class nsPresContext;
 class nsWindowSizes;
 
-namespace mozilla {
-
-enum class CSSPseudoElementType : uint8_t;
-class ComputedStyle;
+#define STYLE_STRUCT(name_) struct nsStyle##name_;
+#include "nsStyleStructList.h"
+#undef STYLE_STRUCT
 
 extern "C" {
   void Servo_ComputedStyle_AddRef(const mozilla::ComputedStyle* aStyle);
   void Servo_ComputedStyle_Release(const mozilla::ComputedStyle* aStyle);
   void Gecko_ComputedStyle_Destroy(mozilla::ComputedStyle*);
 }
 
+namespace mozilla {
+
+enum class CSSPseudoElementType : uint8_t;
+class ComputedStyle;
+
 /**
  * A ComputedStyle represents the computed style data for an element.  The
  * computed style data are stored in a set of structs (see nsStyleStruct.h) that
  * are cached either on the ComputedStyle or in the rule tree (see nsRuleNode.h
  * for a description of this caching and how the cached structs are shared).
  *
  * Since the data in |nsIStyleRule|s and |nsRuleNode|s are immutable (with a few
  * exceptions, like system color changes), the data in an ComputedStyle are also

--- a/layout/style/ServoStyleSet.h
+++ b/layout/style/ServoStyleSet.h
@@ -3,48 +3,52 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #ifndef mozilla_ServoStyleSet_h
 #define mozilla_ServoStyleSet_h
 
 #include "mozilla/AtomArray.h"
-#include "mozilla/EffectCompositor.h"
 #include "mozilla/EnumeratedArray.h"
 #include "mozilla/EventStates.h"
 #include "mozilla/MediaFeatureChange.h"
 #include "mozilla/PostTraversalTask.h"
 #include "mozilla/ServoBindingTypes.h"
-#include "mozilla/ServoElementSnapshot.h"
 #include "mozilla/ServoBindings.h"
 #include "mozilla/ServoUtils.h"
 #include "mozilla/StyleSheetInlines.h"
 #include "mozilla/SheetType.h"
 #include "mozilla/UniquePtr.h"
 #include "MainThreadUtils.h"
 #include "nsCSSPseudoElements.h"
 #include "nsCSSAnonBoxes.h"
 #include "nsChangeHint.h"
+#include "nsCoord.h"
 #include "nsAtom.h"
 #include "nsIMemoryReporter.h"
 #include "nsTArray.h"
 
 namespace mozilla {
+namespace css {
+class Rule;
+} // namespace css
 namespace dom {
 class Element;
+class ShadowRoot;
 } // namespace dom
-class CSSStyleSheet;
 class ServoRestyleManager;
 class ServoStyleSheet;
 struct Keyframe;
 class ServoElementSnapshotTable;
 class ComputedStyle;
 class ServoStyleRuleMap;
+class StyleSheet;
 } // namespace mozilla
+class gfxFontFeatureValueSet;
 class nsCSSCounterStyleRule;
 class nsIContent;
 class nsIDocument;
 class nsPresContext;
 struct nsTimingFunction;
 struct RawServoRuleNode;
 struct TreeMatchContext;
 
@@ -466,17 +470,17 @@ public:
    * is an element and which has no pseudo on its ComputedStyle (so it's the
    * actual style for the element being passed).
    */
   already_AddRefed<ComputedStyle>
   ReparentComputedStyle(ComputedStyle* aComputedStyle,
                         ComputedStyle* aNewParent,
                         ComputedStyle* aNewParentIgnoringFirstLine,
                         ComputedStyle* aNewLayoutParent,
-                        Element* aElement);
+                        dom::Element* aElement);
 
 private:
   friend class AutoSetInServoTraversal;
   friend class AutoPrepareTraversal;
 
   bool ShouldTraverseInParallel() const;
 
   /**

--- a/layout/style/StreamLoader.h
+++ b/layout/style/StreamLoader.h
@@ -2,16 +2,17 @@
 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #ifndef mozilla_css_StreamLoader_h
 #define mozilla_css_StreamLoader_h
 
+#include "nsIStreamListener.h"
 #include "nsString.h"
 #include "mozilla/css/SheetLoadData.h"
 
 class nsIInputStream;
 
 namespace mozilla {
 namespace css {
 

--- a/modules/libpref/Preferences.cpp
+++ b/modules/libpref/Preferences.cpp
@@ -24,16 +24,17 @@
 #include "mozilla/Omnijar.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/ResultExtensions.h"
 #include "mozilla/ScopeExit.h"
 #include "mozilla/Services.h"
 #include "mozilla/ServoStyleSet.h"
 #include "mozilla/StaticPrefs.h"
 #include "mozilla/SyncRunnable.h"
+#include "mozilla/SystemGroup.h"
 #include "mozilla/Telemetry.h"
 #include "mozilla/UniquePtrExtensions.h"
 #include "mozilla/URLPreloader.h"
 #include "mozilla/Variant.h"
 #include "mozilla/Vector.h"
 #include "nsAppDirectoryServiceDefs.h"
 #include "nsAutoPtr.h"
 #include "nsCategoryManagerUtils.h"