Split SpellCheckPanel off SpellCheckProvider

components/spellcheck/renderer/spellcheck_panel.h

+// 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.
+
+#ifndef COMPONENTS_SPELLCHECK_RENDERER_SPELLCHECK_PANEL_H
+#define COMPONENTS_SPELLCHECK_RENDERER_SPELLCHECK_PANEL_H
+
+#include "base/macros.h"
+#include "components/spellcheck/spellcheck_build_features.h"
+#include "content/public/renderer/render_view_observer.h"
+#include "content/public/renderer/render_view_observer_tracker.h"
+#include "third_party/WebKit/public/web/WebSpellCheckClient.h"
+
+class SpellCheckPanel
+    : public content::RenderViewObserver,
+      public content::RenderViewObserverTracker<SpellCheckPanel>,
+      public blink::WebSpellCheckClient {
+ public:
+  SpellCheckPanel(content::RenderView* render_view);

[please use gerrit instead, 2017/04/05 15:17:40]

explicit.

[Xiaocheng, 2017/04/05 18:13:32]

Done.

+  ~SpellCheckPanel() override;
+
+  // RenderViewObserver implementation.
+  bool OnMessageReceived(const IPC::Message& message) override;
+
+ private:
+  // RenderViewObserver implementation.
+  void OnDestruct() override;
+
+  // blink::WebSpellCheckClient implementation.
+  void showSpellingUI(bool show) override;
+  bool isShowingSpellingUI() override;
+  void updateSpellingUIWithMisspelledWord(
+      const blink::WebString& word) override;
+
+#if BUILDFLAG(USE_BROWSER_SPELLCHECKER)
+  void OnAdvanceToNextMisspelling();
+  void OnToggleSpellPanel(bool is_currently_visible);
+#endif

[please use gerrit instead, 2017/04/05 15:17:40]

Only Mac has a "spelling UI". USE_BROWSER_SPELLCHECKER is always true on Mac.
Can you remove the #if check and make sure that this file is used/compiled only
on Mac?

[Xiaocheng, 2017/04/05 18:13:32]

In order not to break anything, I'm not going to introduce any behavior change
in this patch.

I added a TODO, and will do that after fixing the bug.

+
+  // True if the browser is showing the spelling panel for us.
+  bool spelling_panel_visible_;
+
+  DISALLOW_COPY_AND_ASSIGN(SpellCheckPanel);
+};
+
+#endif