--- a/dom/html/HTMLInputElement.cpp
+++ b/dom/html/HTMLInputElement.cpp
@@ -16,17 +16,16 @@
 #include "mozilla/dom/GetFilesHelper.h"
 #include "nsAttrValueInlines.h"
 #include "nsCRTGlue.h"
 
 #include "nsIDOMHTMLInputElement.h"
 #include "nsITextControlElement.h"
 #include "nsIDOMNSEditableElement.h"
 #include "nsIRadioVisitor.h"
-#include "nsIPhonetic.h"
 #include "InputType.h"
 
 #include "HTMLFormSubmissionConstants.h"
 #include "mozilla/Telemetry.h"
 #include "nsIControllers.h"
 #include "nsIStringBundle.h"
 #include "nsFocusManager.h"
 #include "nsColorControlFrame.h"
@@ -1264,17 +1263,16 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 NS_IMPL_ADDREF_INHERITED(HTMLInputElement, Element)
 NS_IMPL_RELEASE_INHERITED(HTMLInputElement, Element)
 
 // QueryInterface implementation for HTMLInputElement
 NS_INTERFACE_TABLE_HEAD_CYCLE_COLLECTION_INHERITED(HTMLInputElement)
   NS_INTERFACE_TABLE_INHERITED(HTMLInputElement,
                                nsIDOMHTMLInputElement,
                                nsITextControlElement,
-                               nsIPhonetic,
                                imgINotificationObserver,
                                nsIImageLoadingContent,
                                imgIOnloadBlocker,
                                nsIDOMNSEditableElement,
                                nsIConstraintValidation)
 NS_INTERFACE_TABLE_TAIL_INHERITING(nsGenericHTMLFormElementWithState)
 
 // nsIConstraintValidation
@@ -6531,29 +6529,16 @@ HTMLInputElement::SetSelectionDirection(
     return;
   }
 
   nsTextEditorState* state = GetEditorState();
   MOZ_ASSERT(state, "SupportsTextSelection came back true!");
   state->SetSelectionDirection(aDirection, aRv);
 }
 
-NS_IMETHODIMP
-HTMLInputElement::GetPhonetic(nsAString& aPhonetic)
-{
-  aPhonetic.Truncate();
-  nsIFormControlFrame* formControlFrame = GetFormControlFrame(true);
-  nsITextControlFrame* textControlFrame = do_QueryFrame(formControlFrame);
-  if (textControlFrame) {
-    textControlFrame->GetPhonetic(aPhonetic);
-  }
-
-  return NS_OK;
-}
-
 #ifdef ACCESSIBILITY
 /*static*/ nsresult
 FireEventForAccessibility(nsIDOMHTMLInputElement* aTarget,
                           nsPresContext* aPresContext,
                           const nsAString& aEventType)
 {
   nsCOMPtr<mozilla::dom::Element> element = do_QueryInterface(aTarget);
   RefPtr<Event> event = NS_NewDOMEvent(element, aPresContext, nullptr);

--- a/dom/html/HTMLInputElement.h
+++ b/dom/html/HTMLInputElement.h
@@ -8,17 +8,16 @@
 #define mozilla_dom_HTMLInputElement_h
 
 #include "mozilla/Attributes.h"
 #include "nsGenericHTMLElement.h"
 #include "nsImageLoadingContent.h"
 #include "nsIDOMHTMLInputElement.h"
 #include "nsITextControlElement.h"
 #include "nsITimer.h"
-#include "nsIPhonetic.h"
 #include "nsIDOMNSEditableElement.h"
 #include "nsCOMPtr.h"
 #include "nsIConstraintValidation.h"
 #include "mozilla/UniquePtr.h"
 #include "mozilla/dom/BindingDeclarations.h"
 #include "mozilla/dom/HTMLFormElement.h" // for HasEverTriedInvalidSubmit()
 #include "mozilla/dom/HTMLInputElementBinding.h"
 #include "mozilla/dom/Promise.h"
@@ -123,17 +122,16 @@ public:
     nsCOMPtr<nsIContentPref> mResult;
   };
 };
 
 class HTMLInputElement final : public nsGenericHTMLFormElementWithState,
                                public nsImageLoadingContent,
                                public nsIDOMHTMLInputElement,
                                public nsITextControlElement,
-                               public nsIPhonetic,
                                public nsIDOMNSEditableElement,
                                public nsIConstraintValidation
 {
   friend class AfterSetFilesOrDirectoriesCallback;
   friend class DispatchChangeEventCallback;
   friend class ::InputType;
 
 public:
@@ -169,19 +167,16 @@ public:
   virtual bool IsInteractiveHTMLContent(bool aIgnoreTabindex) const override;
 
   // EventTarget
   virtual void AsyncEventRunning(AsyncEventDispatcher* aEvent) override;
 
   // nsIDOMHTMLInputElement
   NS_DECL_NSIDOMHTMLINPUTELEMENT
 
-  // nsIPhonetic
-  NS_DECL_NSIPHONETIC
-
   // nsIDOMNSEditableElement
   NS_IMETHOD GetEditor(nsIEditor** aEditor) override
   {
     return nsGenericHTMLElement::GetEditor(aEditor);
   }
 
   NS_IMETHOD SetUserInput(const nsAString& aInput) override;
 
@@ -870,18 +865,16 @@ public:
 
   bool MozIsTextField(bool aExcludePassword);
 
   nsIEditor* GetEditor();
 
   void SetUserInput(const nsAString& aInput,
                     nsIPrincipal& aSubjectPrincipal);
 
-  // XPCOM GetPhonetic() is OK
-
   /**
    * If aValue contains a valid floating-point number in the format specified
    * by the HTML 5 spec:
    *
    *   http://www.whatwg.org/specs/web-apps/current-work/multipage/common-microsyntaxes.html#floating-point-numbers
    *
    * then this function will return the number parsed as a Decimal, otherwise
    * it will return a Decimal for which Decimal::isFinite() will return false.

--- a/dom/html/moz.build
+++ b/dom/html/moz.build
@@ -22,17 +22,16 @@ MOCHITEST_CHROME_MANIFESTS += [
 
 BROWSER_CHROME_MANIFESTS += ['test/browser.ini']
 
 XPIDL_SOURCES += [
     'nsIDateTimeInputArea.idl',
     'nsIFormSubmitObserver.idl',
     'nsIImageDocument.idl',
     'nsIMenuBuilder.idl',
-    'nsIPhonetic.idl',
 ]
 
 XPIDL_MODULE = 'content_html'
 
 EXPORTS += [
     'nsGenericHTMLElement.h',
     'nsHTMLDNSPrefetch.h',
     'nsIConstraintValidation.h',

deleted file mode 100644
--- a/dom/html/nsIPhonetic.idl
+++ /dev/null
@@ -1,22 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* 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/. */
-
-#include "nsISupports.idl"
-
-/** 
- * This interface is used to get the phonetic value of the input text.
- * It can be used to get corresponding phonetic value for ideographic text.
- * The interface can be retrieved by calling QI to the interface 
- * which implements the phonetic interface.
- */
-
-[uuid(BC6EA726-AB56-46b6-A21A-AA7B76D6818F)]
-interface nsIPhonetic : nsISupports
-{
-  /**
-   * phonetic get the phonetic value of the input text
-   */
-  readonly attribute DOMString phonetic;
-};

--- a/dom/webidl/HTMLInputElement.webidl
+++ b/dom/webidl/HTMLInputElement.webidl
@@ -212,24 +212,17 @@ partial interface HTMLInputElement {
 
   [Throws, Pref="dom.input.dirpicker"]
   Promise<sequence<File>> getFiles(optional boolean recursiveFlag = false);
 
   [Throws, Pref="dom.input.dirpicker"]
   void chooseDirectory();
 };
 
-[NoInterfaceObject]
-interface MozPhonetic {
-  [Pure, ChromeOnly]
-  readonly attribute DOMString phonetic;
-};
-
 HTMLInputElement implements MozImageLoadingContent;
-HTMLInputElement implements MozPhonetic;
 
 // Webkit/Blink
 partial interface HTMLInputElement {
   [Pref="dom.webkitBlink.filesystem.enabled", Frozen, Cached, Pure]
   readonly attribute sequence<FileSystemEntry> webkitEntries;
 
   [Pref="dom.webkitBlink.dirPicker.enabled", BinaryName="WebkitDirectoryAttr", SetterThrows]
           attribute boolean webkitdirectory;

--- a/editor/libeditor/EditorBase.cpp
+++ b/editor/libeditor/EditorBase.cpp
@@ -123,17 +123,16 @@ using namespace widget;
 
 /*****************************************************************************
  * mozilla::EditorBase
  *****************************************************************************/
 
 EditorBase::EditorBase()
   : mPlaceHolderName(nullptr)
   , mSelState(nullptr)
-  , mPhonetic(nullptr)
   , mModCount(0)
   , mFlags(0)
   , mUpdateCount(0)
   , mPlaceHolderBatch(0)
   , mAction(EditAction::none)
   , mIMETextOffset(0)
   , mIMETextLength(0)
   , mDirection(eNone)
@@ -155,18 +154,16 @@ EditorBase::~EditorBase()
 
   if (mComposition) {
     mComposition->OnEditorDestroyed();
     mComposition = nullptr;
   }
   // If this editor is still hiding the caret, we need to restore it.
   HideCaret(false);
   mTxnMgr = nullptr;
-
-  delete mPhonetic;
 }
 
 NS_IMPL_CYCLE_COLLECTION_CLASS(EditorBase)
 
 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(EditorBase)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mRootElement)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mInlineSpellChecker)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mTxnMgr)
@@ -196,17 +193,16 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDocStateListeners)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mEventTarget)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mEventListener)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mSavedSel);
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mRangeUpdater);
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(EditorBase)
- NS_INTERFACE_MAP_ENTRY(nsIPhonetic)
  NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
  NS_INTERFACE_MAP_ENTRY(nsIEditor)
  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIEditor)
 NS_INTERFACE_MAP_END
 
 NS_IMPL_CYCLE_COLLECTING_ADDREF(EditorBase)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(EditorBase)
 
@@ -2083,19 +2079,16 @@ EditorBase::EnsureComposition(WidgetComp
 
 nsresult
 EditorBase::BeginIMEComposition(WidgetCompositionEvent* aCompositionEvent)
 {
   MOZ_ASSERT(!mComposition, "There is composition already");
   if (!EnsureComposition(aCompositionEvent)) {
     return NS_OK;
   }
-  if (mPhonetic) {
-    mPhonetic->Truncate(0);
-  }
   return NS_OK;
 }
 
 void
 EditorBase::EndIMEComposition()
 {
   NS_ENSURE_TRUE_VOID(mComposition); // nothing to do
 
@@ -2122,28 +2115,16 @@ EditorBase::EndIMEComposition()
   mComposition->EndHandlingComposition(this);
   mComposition = nullptr;
 
   // notify editor observers of action
   NotifyEditorObservers(eNotifyEditorObserversOfEnd);
 }
 
 NS_IMETHODIMP
-EditorBase::GetPhonetic(nsAString& aPhonetic)
-{
-  if (mPhonetic) {
-    aPhonetic = *mPhonetic;
-  } else {
-    aPhonetic.Truncate(0);
-  }
-
-  return NS_OK;
-}
-
-NS_IMETHODIMP
 EditorBase::ForceCompositionEnd()
 {
   nsCOMPtr<nsIPresShell> ps = GetPresShell();
   if (!ps) {
     return NS_ERROR_NOT_AVAILABLE;
   }
   nsPresContext* pc = ps->GetPresContext();
   if (!pc) {
@@ -2517,32 +2498,16 @@ EditorBase::InsertTextIntoTextNodeImpl(c
   // aSuppressIME is used when editor must insert text, yet this text is not
   // part of the current IME operation. Example: adjusting whitespace around an
   // IME insertion.
   if (ShouldHandleIMEComposition() && !aSuppressIME) {
     if (!mIMETextNode) {
       mIMETextNode = &aTextNode;
       mIMETextOffset = aOffset;
     }
-    // Modify mPhonetic with raw text input clauses.
-    const TextRangeArray* ranges = mComposition->GetRanges();
-    for (uint32_t i = 0; i < (ranges ? ranges->Length() : 0); ++i) {
-      const TextRange& textRange = ranges->ElementAt(i);
-      if (!textRange.Length() ||
-          textRange.mRangeType != TextRangeType::eRawClause) {
-        continue;
-      }
-      if (!mPhonetic) {
-        mPhonetic = new nsString();
-      }
-      nsAutoString stringToInsert(aStringToInsert);
-      stringToInsert.Mid(*mPhonetic,
-                         textRange.mStartOffset, textRange.Length());
-    }
-
     transaction = CreateTxnForComposition(aStringToInsert);
     isIMETransaction = true;
     // All characters of the composition string will be replaced with
     // aStringToInsert.  So, we need to emulate to remove the composition
     // string.
     insertedTextNode = mIMETextNode;
     insertedOffset = mIMETextOffset;
     mIMETextLength = aStringToInsert.Length();

--- a/editor/libeditor/EditorBase.h
+++ b/editor/libeditor/EditorBase.h
@@ -12,17 +12,16 @@
 #include "mozilla/StyleSheet.h"   // for StyleSheet
 #include "mozilla/UniquePtr.h"
 #include "mozilla/dom/Text.h"
 #include "nsCOMPtr.h"                   // for already_AddRefed, nsCOMPtr
 #include "nsCycleCollectionParticipant.h"
 #include "nsGkAtoms.h"
 #include "nsIEditor.h"                  // for nsIEditor, etc.
 #include "nsIObserver.h"                // for NS_DECL_NSIOBSERVER, etc.
-#include "nsIPhonetic.h"                // for NS_DECL_NSIPHONETIC, etc.
 #include "nsIPlaintextEditor.h"         // for nsIPlaintextEditor, etc.
 #include "nsISelectionController.h"     // for nsISelectionController constants
 #include "nsISupportsImpl.h"            // for EditorBase::Release, etc.
 #include "nsIWeakReferenceUtils.h"      // for nsWeakPtr
 #include "nsLiteralString.h"            // for NS_LITERAL_STRING
 #include "nsString.h"                   // for nsCString
 #include "nsTArray.h"                   // for nsTArray and nsAutoTArray
 #include "nsWeakReference.h"            // for nsSupportsWeakReference
@@ -141,17 +140,16 @@ struct IMEState;
  * Implementation of an editor object.  it will be the controller/focal point
  * for the main editor services. i.e. the GUIManager, publishing, transaction
  * manager, event interfaces. the idea for the event interfaces is to have them
  * delegate the actual commands to the editor independent of the XPFE
  * implementation.
  */
 class EditorBase : public nsIEditor
                  , public nsSupportsWeakReference
-                 , public nsIPhonetic
 {
 public:
   typedef dom::Element Element;
   typedef dom::Selection Selection;
   typedef dom::Text Text;
 
   enum IterDirection
   {
@@ -191,19 +189,16 @@ public:
     eNotifyEditorObserversOfBefore,
     eNotifyEditorObserversOfCancel
   };
   void NotifyEditorObservers(NotificationForEditorObservers aNotification);
 
   // nsIEditor methods
   NS_DECL_NSIEDITOR
 
-  // nsIPhonetic
-  NS_DECL_NSIPHONETIC
-
 public:
   virtual bool IsModifiableNode(nsINode* aNode);
 
   virtual nsresult InsertTextImpl(const nsAString& aStringToInsert,
                                   nsCOMPtr<nsINode>* aInOutNode,
                                   int32_t* aInOutOffset,
                                   nsIDocument* aDoc);
   nsresult InsertTextIntoTextNodeImpl(const nsAString& aStringToInsert,
@@ -1005,17 +1000,16 @@ protected:
   // Weak reference to placeholder for begin/end batch purposes.
   nsWeakPtr mPlaceHolderTxn;
   // Weak reference to the nsIDOMDocument.
   nsWeakPtr mDocWeak;
   // Name of placeholder transaction.
   nsIAtom* mPlaceHolderName;
   // Saved selection state for placeholder transaction batching.
   mozilla::UniquePtr<SelectionState> mSelState;
-  nsString* mPhonetic;
   // IME composition this is not null between compositionstart and
   // compositionend.
   RefPtr<TextComposition> mComposition;
 
   // Listens to all low level actions on the doc.
   typedef AutoTArray<OwningNonNull<nsIEditActionListener>, 5>
             AutoActionListenerArray;
   AutoActionListenerArray mActionListeners;

--- a/layout/forms/nsITextControlFrame.h
+++ b/layout/forms/nsITextControlFrame.h
@@ -27,18 +27,16 @@ public:
 
   NS_IMETHOD    SetSelectionRange(uint32_t aSelectionStart,
                                   uint32_t aSelectionEnd,
                                   SelectionDirection aDirection = eNone) = 0;
 
   NS_IMETHOD    GetOwnedSelectionController(nsISelectionController** aSelCon) = 0;
   virtual nsFrameSelection* GetOwnedFrameSelection() = 0;
 
-  virtual nsresult GetPhonetic(nsAString& aPhonetic) = 0;
-
   /**
    * Ensure editor is initialized with the proper flags and the default value.
    * @throws NS_ERROR_NOT_INITIALIZED if mEditor has not been created
    * @throws various and sundry other things
    */
   virtual nsresult EnsureEditorInitialized() = 0;
 
   virtual nsresult ScrollSelectionIntoView() = 0;

--- a/layout/forms/nsTextControlFrame.cpp
+++ b/layout/forms/nsTextControlFrame.cpp
@@ -8,17 +8,16 @@
 #include "nsCOMPtr.h"
 #include "nsFontMetrics.h"
 #include "nsTextControlFrame.h"
 #include "nsIPlaintextEditor.h"
 #include "nsCaret.h"
 #include "nsCSSPseudoElements.h"
 #include "nsGenericHTMLElement.h"
 #include "nsIEditor.h"
-#include "nsIPhonetic.h"
 #include "nsTextFragment.h"
 #include "nsIDOMHTMLTextAreaElement.h"
 #include "nsNameSpaceManager.h"
 #include "nsFormControlFrame.h" //for registering accesskeys
 
 #include "nsIContent.h"
 #include "nsPresContext.h"
 #include "nsRenderingContext.h"
@@ -1092,32 +1091,16 @@ nsTextControlFrame::GetText(nsString& aT
     if (textArea) {
       rv = textArea->GetValue(aText);
     }
   }
   return rv;
 }
 
 
-nsresult
-nsTextControlFrame::GetPhonetic(nsAString& aPhonetic)
-{
-  aPhonetic.Truncate(0);
-
-  nsCOMPtr<nsIEditor> editor;
-  nsresult rv = GetEditor(getter_AddRefs(editor));
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  nsCOMPtr<nsIPhonetic> phonetic = do_QueryInterface(editor);
-  if (phonetic) {
-    phonetic->GetPhonetic(aPhonetic);
-  }
-  return NS_OK;
-}
-
 ///END NSIFRAME OVERLOADS
 /////BEGIN PROTECTED METHODS
 
 bool
 nsTextControlFrame::GetMaxLength(int32_t* aSize)
 {
   *aSize = -1;
 

--- a/layout/forms/nsTextControlFrame.h
+++ b/layout/forms/nsTextControlFrame.h
@@ -143,18 +143,16 @@ public:
 
   NS_IMETHOD    GetEditor(nsIEditor **aEditor) override;
   NS_IMETHOD    SetSelectionRange(uint32_t aSelectionStart,
                                   uint32_t aSelectionEnd,
                                   SelectionDirection aDirection = eNone) override;
   NS_IMETHOD    GetOwnedSelectionController(nsISelectionController** aSelCon) override;
   virtual nsFrameSelection* GetOwnedFrameSelection() override;
 
-  nsresult GetPhonetic(nsAString& aPhonetic) override;
-
   /**
    * Ensure mEditor is initialized with the proper flags and the default value.
    * @throws NS_ERROR_NOT_INITIALIZED if mEditor has not been created
    * @throws various and sundry other things
    */
   virtual nsresult EnsureEditorInitialized() override;
 
 //==== END NSITEXTCONTROLFRAME