Convert Spellcheck host MessageFilter IPC to mojo

components/spellcheck/common/spellcheck.mojom

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 module spellcheck.mojom;
 
 import "mojo/common/file.mojom";
+import "mojo/common/string16.mojom";
 
 // Render process interface exposed to the browser for receiving process-
 // wide spellcheck control and updates from the browser process.
 //
 interface SpellChecker {
   // Initialize the render process spellchecker. Called after startup and
   // also in response to a render process RequestDictionary request.
   Initialize(array<SpellCheckBDictLanguage> dictionaries,
              array<string> custom_words,
              bool enable);
 
   // Custom dictionary words have been added or removed: update the local
   // custom word list.
   CustomDictionaryChanged(array<string> words_added,
                           array<string> words_removed);
 };
 
 struct SpellCheckBDictLanguage {
   mojo.common.mojom.File? file;
   string language;
 };
+
+// Browser process interface exposed to the renderer for requesting spell-
+// check host services.
+//
+interface SpellCheckHost {
+  // Asks the browser to initialize the renderer's spellchecker: the spell
+  // checker initialize call arrives on spellcheck::mojom::SpellChecker in
+  // async response to this request.
+  RequestDictionary();
+
+  // Tracks spell checking occurrences to collect histograms, where |word|
+  // was checked, and |misspelled| is true if |word| was misspelt.
+  NotifyChecked(mojo.common.mojom.String16 word, bool misspelled);
+
+  // Asks the host to spellcheck the |text| using a remote Spelling server
+  // to do the spellchecking. If the remote Spelling server is available,
+  // returns |success| true, and the spellchecked |results|. Note this API
+  // requires a !BUILDFLAG(USE_BROWSER_SPELLCHECKER) build.
+  CallSpellingService(mojo.common.mojom.String16 text) =>
+      (bool success, array<SpellCheckResult> results);
+};
+
+[Native]
+struct SpellCheckResult;