cc: Remove SurfaceDependencies type

cc/surfaces/surface_dependency_tracker.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 CC_SURFACES_SURFACE_DEPENDENCY_TRACKER_H_
 #define CC_SURFACES_SURFACE_DEPENDENCY_TRACKER_H_
 
 #include "cc/scheduler/begin_frame_source.h"
 #include "cc/surfaces/pending_frame_observer.h"
 #include "cc/surfaces/surface.h"
@@ skipping 35 matching lines @@
 
   // BeginFrameObserver implementation.
   void OnBeginFrame(const BeginFrameArgs& args) override;
   const BeginFrameArgs& LastUsedBeginFrameArgs() const override;
   void OnBeginFrameSourcePausedChanged(bool paused) override;
 
   // PendingFrameObserver implementation:
   void OnSurfaceActivated(Surface* surface) override;
   void OnSurfaceDependenciesChanged(
       Surface* surface,
-      const SurfaceDependencies& added_dependencies,
-      const SurfaceDependencies& removed_dependencies) override;
+      const base::flat_set<SurfaceId>& added_dependencies,
+      const base::flat_set<SurfaceId>& removed_dependencies) override;
   void OnSurfaceDiscarded(Surface* surface) override;
 
   // SurfaceObserver implementation:
   void OnSurfaceCreated(const SurfaceInfo& surface_info) override;
   void OnSurfaceDamaged(const SurfaceId& surface_id, bool* changed) override;
 
  private:
   // Informs all Surfaces with pending frames blocked on the provided
   // |surface_id| that there is now an active frame available in Surface
   // corresponding to |surface_id|.
@@ skipping 22 matching lines @@
   // The set of SurfaceIds to which corresponding CompositorFrames have not
   // arrived by the time their deadline fired.
   base::flat_set<SurfaceId> late_surfaces_by_id_;
 
   DISALLOW_COPY_AND_ASSIGN(SurfaceDependencyTracker);
 };
 
 }  // namespace cc
 
 #endif  // CC_SURFACES_SURFACE_DEPENDENCY_TRACKER_H_