Expose Blimp dependencies to the embedder

blimp/client/public/compositor/compositor_dependencies.h

Index: blimp/client/public/compositor/compositor_dependencies.h
diff --git a/blimp/client/public/compositor/compositor_dependencies.h b/blimp/client/public/compositor/compositor_dependencies.h
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+++ b/blimp/client/public/compositor/compositor_dependencies.h
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+// 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 BLIMP_CLIENT_PUBLIC_COMPOSITOR_COMPOSITOR_DEPENDENCIES_H_
+#define BLIMP_CLIENT_PUBLIC_COMPOSITOR_COMPOSITOR_DEPENDENCIES_H_
+
+#include "base/callback.h"
+#include "base/memory/ptr_util.h"
+
+namespace cc {
+class ContextProvider;
+class LayerTreeSettings;
+class SurfaceManager;
+}  // namespace cc
+
+namespace gpu {
+class GpuMemoryBufferManager;
+}  // namespace gpu
+
+namespace blimp {
+namespace client {
+
+// A set of compositor dependencies that must be provided by the embedder.  This
+// is expected to outlive all BlimpContents instances.
+class CompositorDependencies {
+ public:
+  using ContextProviderCallback =
+      base::Callback<void(const scoped_refptr<cc::ContextProvider>&)>;
+
+  virtual ~CompositorDependencies() = default;
+
+  // Settings used to create all BlimpCompositor instances.
+  virtual cc::LayerTreeSettings* GetLayerTreeSettings() = 0;
+  virtual gpu::GpuMemoryBufferManager* GetGpuMemoryBufferManager() = 0;
+  virtual cc::SurfaceManager* GetSurfaceManager() = 0;
+  virtual uint32_t AllocateSurfaceId() = 0;
+
+  // This call may return synchronously if the ContextProvider has already been
+  // created.
+  virtual void GetContextProvider(const ContextProviderCallback& callback) = 0;
+};
+
+}  // namespace client
+}  // namespace blimp
+
+#endif  // BLIMP_CLIENT_PUBLIC_COMPOSITOR_COMPOSITOR_DEPENDENCIES_H_