Bug 1625855 - Replace MOZ_MUST_USE with [[nodiscard]] in layout. r=TYLin

Differential Revision: https://phabricator.services.mozilla.com/D68751

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

layout/base/AccessibleCaretManager.h

@@ -230,7 +230,7 @@ class AccessibleCaretManager {
   // See the mRefCnt assertions in AccessibleCaretEventHub.
   //
   // Returns whether mPresShell we're holding is still valid.
-  MOZ_MUST_USE MOZ_CAN_RUN_SCRIPT bool FlushLayout();
+  [[nodiscard]] MOZ_CAN_RUN_SCRIPT bool FlushLayout();
 
   dom::Element* GetEditingHostForFrame(nsIFrame* aFrame) const;
   dom::Selection* GetSelection() const;

layout/forms/nsTextControlFrame.h

@@ -327,8 +327,8 @@ class nsTextControlFrame : public nsContainerFrame,
 
   void CacheValue(const nsAString& aValue) { mCachedValue.Assign(aValue); }
 
-  MOZ_MUST_USE bool CacheValue(const nsAString& aValue,
-                               const mozilla::fallible_t& aFallible) {
+  [[nodiscard]] bool CacheValue(const nsAString& aValue,
+                                const mozilla::fallible_t& aFallible) {
     if (!mCachedValue.Assign(aValue, aFallible)) {
       ClearCachedValue();
       return false;

layout/generic/AspectRatio.h

@@ -39,7 +39,7 @@ struct AspectRatio {
   }
 
   // Inverts the ratio, in order to get the height / width ratio.
-  MOZ_MUST_USE AspectRatio Inverted() const {
+  [[nodiscard]] AspectRatio Inverted() const {
     return *this ? AspectRatio(1.0f / mRatio) : *this;
   }
 

layout/generic/nsIFrame.h

@@ -2040,7 +2040,7 @@ class nsIFrame : public nsQueryFrame {
    *
    * Returns whether the image was in fact associated with the frame.
    */
-  MOZ_MUST_USE bool AssociateImage(const mozilla::StyleImage&);
+  [[nodiscard]] bool AssociateImage(const mozilla::StyleImage&);
 
   /**
    * This needs to be called if the above caller returned true, once the above
@@ -3720,7 +3720,7 @@ class nsIFrame : public nsQueryFrame {
   }
 
   template <typename T>
-  MOZ_MUST_USE FrameProperties::PropertyType<T> TakeProperty(
+  [[nodiscard]] FrameProperties::PropertyType<T> TakeProperty(
       FrameProperties::Descriptor<T> aProperty, bool* aFoundResult = nullptr) {
     return mProperties.Take(aProperty, aFoundResult);
   }

layout/style/ImportScanner.h

@@ -67,7 +67,7 @@ struct ImportScanner final {
   };
 
   void EmitUrl();
-  MOZ_MUST_USE State Scan(char16_t aChar);
+  [[nodiscard]] State Scan(char16_t aChar);
 
   static constexpr const uint32_t kMaxRuleNameLength = 7;  // (charset, import)
 

layout/svg/AutoReferenceChainGuard.h

@@ -118,7 +118,7 @@ class MOZ_RAII AutoReferenceChainGuard {
    * If it returns false then an error message will be reported to the DevTools
    * console (only once).
    */
-  MOZ_MUST_USE bool Reference() {
+  [[nodiscard]] bool Reference() {
     if (MOZ_UNLIKELY(*mFrameInUse)) {
       mBrokeReference = true;
       ReportErrorToConsole();