Add a mojo channel for frame messages.

content/renderer/input/frame_input_handler_impl.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 CONTENT_RENDERER_INPUT_FRAME_INPUT_HANDLER_IMPL_H_
+#define CONTENT_RENDERER_INPUT_FRAME_INPUT_HANDLER_IMPL_H_
+
+#include "base/memory/ref_counted.h"
+#include "content/common/input/input_handler.mojom.h"
+#include "content/renderer/render_frame_impl.h"
+#include "mojo/public/cpp/bindings/binding.h"
+
+namespace content {
+class MainThreadEventQueue;
+
+class FrameInputHandlerImpl

[dcheng, 2017/05/17 04:49:06]

I think this class could probably use a class-level comment to document the
complexities of input handling--as someone who doesn't really touch input, it's
not super obvious why having an input event queue means we need to handle
messages on the compositor thread.

[dtapuska, 2017/05/17 17:08:08]

Done.

+    : public mojom::FrameInputHandler,
+      public base::RefCountedThreadSafe<FrameInputHandlerImpl> {
+ public:
+  static void CreateMojoService(
+      RenderFrameImpl* render_frame,
+      const service_manager::BindSourceInfo& source_info,
+      mojom::FrameInputHandlerRequest request);
+
+  void SetCompositionFromExistingText(
+      int32_t start,
+      int32_t end,
+      const std::vector<ui::CompositionUnderline>& underlines) override;
+  void ExtendSelectionAndDelete(int32_t before, int32_t after) override;
+  void DeleteSurroundingText(int32_t before, int32_t after) override;
+  void DeleteSurroundingTextInCodePoints(int32_t before,
+                                         int32_t after) override;
+  void SetEditableSelectionOffsets(int32_t start, int32_t end) override;
+  void ExecuteEditCommand(const std::string& command,
+                          const base::Optional<std::string>& value) override;
+  void Undo() override;
+  void Redo() override;
+  void Cut() override;
+  void Copy() override;
+  void CopyToFindPboard() override;
+  void Paste() override;
+  void PasteAndMatchStyle() override;
+  void Replace(const std::string& word) override;
+  void ReplaceMisspelling(const std::string& word) override;
+  void Delete() override;
+  void SelectAll() override;
+  void CollapseSelection() override;
+  void SelectRange(const gfx::Point& base, const gfx::Point& extent) override;
+  void AdjustSelectionByCharacterOffset(int32_t start, int32_t end) override;
+  void MoveRangeSelectionExtent(const gfx::Point& extent) override;
+
+ protected:
+  friend class base::RefCountedThreadSafe<FrameInputHandlerImpl>;
+  ~FrameInputHandlerImpl() override;
+
+ private:
+  enum class UpdateState { kNone, kIsPasting, kIsSelectingRange };
+
+  class HandlingState {
+   public:
+    HandlingState(RenderFrameImpl* render_frame, UpdateState state);
+    ~HandlingState();
+
+   private:
+    RenderFrameImpl* render_frame_;
+    bool original_select_range_value_;
+    bool original_pasting_value_;
+  };
+
+  FrameInputHandlerImpl(RenderFrameImpl* render_frame,
+                        mojom::FrameInputHandlerRequest request);
+
+  void RunOnMainThread(const base::Closure& closure);
+  void BindOnCompositor(mojom::FrameInputHandlerRequest request);
+  void BindNow(mojom::FrameInputHandlerRequest request);
+  void ExecuteCommandOnMainThread(const std::string& command,
+                                  UpdateState state);
+
+  RenderFrameImpl* GetRenderFrame();
+
+  mojo::Binding<mojom::FrameInputHandler> binding_;
+
+  // |render_frame_| should only be accessed on the main thread. Use
+  // GetRenderFrame so that it will DCHECK this for you.
+  RenderFrameImpl* render_frame_;
+
+  scoped_refptr<MainThreadEventQueue> input_event_queue_;
+  scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;
+
+  DISALLOW_COPY_AND_ASSIGN(FrameInputHandlerImpl);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_INPUT_FRAME_INPUT_HANDLER_IMPL_H_