Add Mojo API for Blink hit testing

content/renderer/input/target_frame_for_input_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_TARGET_FRAME_FOR_INPUT_IMPL_H_
+#define CONTENT_RENDERER_INPUT_TARGET_FRAME_FOR_INPUT_IMPL_H_
+
+#include "base/memory/ref_counted.h"
+#include "content/renderer/render_frame_impl.h"
+#include "mojo/public/cpp/bindings/binding.h"
+#include "services/viz/public/interfaces/hit_test/target_frame_for_input_delegate.mojom.h"
+
+namespace content {
+class MainThreadEventQueue;
+
+// This class provides an implementation of FrameInputHitTest mojo interface.
+class TargetFrameForInputImpl : public viz::mojom::TargetFrameForInputDelegate {
+ public:
+  static void CreateMojoService(
+      base::WeakPtr<RenderFrameImpl> render_frame,
+      viz::mojom::TargetFrameForInputDelegateRequest request);
+
+  void HitTestFrameAt(const gfx::Point& point,
+                      HitTestFrameAtCallback callback) override;
+
+ private:
+  ~TargetFrameForInputImpl() override;
+
+  TargetFrameForInputImpl(
+      base::WeakPtr<RenderFrameImpl> render_frame,
+      viz::mojom::TargetFrameForInputDelegateRequest request);
+
+  void RunOnMainThread(base::OnceClosure closure);
+  void HitTestOnMainThread(const gfx::Point&, HitTestFrameAtCallback);
+
+  void BindNow(viz::mojom::TargetFrameForInputDelegateRequest request);
+  void Release();
+
+  mojo::Binding<viz::mojom::TargetFrameForInputDelegate> binding_;
+
+  // |render_frame_| should only be accessed on the main thread. Use
+  // GetRenderFrame so that it will DCHECK this for you.
+  base::WeakPtr<RenderFrameImpl> render_frame_;
+
+  scoped_refptr<MainThreadEventQueue> input_event_queue_;
+  scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;
+
+  base::WeakPtr<TargetFrameForInputImpl> weak_this_;
+  base::WeakPtrFactory<TargetFrameForInputImpl> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(TargetFrameForInputImpl);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_INPUT_TARGET_FRAME_FOR_INPUT_IMPL_H_