Add ScopedSurfaceRequestManager

content/browser/android/scoped_surface_request_manager.h

+// Copyright 2016 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_BROWSER_ANDROID_SCOPED_SURFACE_REQUEST_MANAGER_H_
+#define CONTENT_BROWSER_ANDROID_SCOPED_SURFACE_REQUEST_MANAGER_H_
+
+#include <string>
+#include <unordered_map>
+
+#include "base/macros.h"
+#include "base/memory/singleton.h"
+#include "content/common/content_export.h"
+#include "gpu/ipc/common/android/scoped_surface_request_conduit.h"
+#include "ui/gl/android/scoped_java_surface.h"
+
+namespace content {
+
+// TODO(tguilbert): Change the 128 bit unguessable token from a base64 string
+// into the token base class, when crbug.com/643857 is completed.
+class CONTENT_EXPORT ScopedSurfaceRequestManager
+    : public gpu::ScopedSurfaceRequestConduit {
+ public:
+  static ScopedSurfaceRequestManager* GetInstance();
+
+  using ScopedSurfaceRequestCB = base::Callback<void(gl::ScopedJavaSurface)>;
+
+  // Registers a request, and returns the |request_token| that should be used to
+  // call Fulfill at a later time. The caller is responsible for unregistering
+  // the request, if it is destroyed before the request is fulfilled.
+  // It is the requester's responsability to check the validity of the final
+  // ScopedJavaSurface (as passing an empty surface is a valid operation).
+  // Must be called on the UI thread.
+  std::string RegisterScopedSurfaceRequest(ScopedSurfaceRequestCB request_cb);
+
+  // Unregisters a request registered under |request_token| if it exists,
+  // no-ops otherwise.
+  // Must be called on the UI thread.
+  void UnregisterScopedSurfaceRequest(std::string request_token);
+
+  // Unregisters and runs the request callback identified by |request_token| if
+  // one exists, no-ops otherwise.
+  // Passing an empty |surface| is a valid operation that will complete the
+  // request.
+  // Can be called from any thread. The request will be run synchonously on the
+  // UI thread.
+  void FulfillScopedSurfaceRequest(std::string request_token,
+                                   gl::ScopedJavaSurface surface);
+
+  // Implementation of ScopedSurfaceRequestConduit.
+  // To be used in the single process case.
+  // Can be called from any thread.
+  void ForwardSurfaceTextureForSurfaceRequest(
+      std::string request_token,
+      gl::SurfaceTexture* surface_texture) override;
+
+  void clear_requests_for_testing() { request_callbacks_.clear(); }
+
+  int request_count_for_testing() { return request_callbacks_.size(); }
+
+ private:
+  friend struct base::DefaultSingletonTraits<ScopedSurfaceRequestManager>;
+
+  // Returns a 128 cryptographically secure token, encoded as a base64 string.
+  std::string GetBase64UnguessableToken();
+
+  // Unregisters and returns the request identified by |request_token|.
+  // Does not acquire |lock_|.
+  ScopedSurfaceRequestCB GetAndUnregisterInternal(std::string request_token);
+
+  // Map used to hold references to the registered callbacks.
+  std::unordered_map<std::string, ScopedSurfaceRequestCB> request_callbacks_;
+
+  ScopedSurfaceRequestManager();
+  ~ScopedSurfaceRequestManager() override;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedSurfaceRequestManager);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_ANDROID_SCOPED_SURFACE_REQUEST_MANAGER_H_