cc: Remove SurfaceDependencies type

SurfaceDependencies is a type alias that was introduced in PendingFrameObserver
but is not used consistently making understanding types more difficult. This
CL simplify removes the type alias.

BUG=none
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

Review-Url: https://codereview.chromium.org/2861713003
Cr-Commit-Position: refs/heads/master@{#469476}

cc/surfaces/pending_frame_observer.h

@@ -11,8 +11,6 @@
 
 namespace cc {
 
-using SurfaceDependencies = base::flat_set<SurfaceId>;
-
 class Surface;
 
 // Clients that wish to observe when the state of a pending CompostiorFrame
@@ -26,8 +24,8 @@ class CC_SURFACES_EXPORT PendingFrameObserver {
   // have changed.
   virtual void OnSurfaceDependenciesChanged(
       Surface* surface,
-      const SurfaceDependencies& added_dependencies,
-      const SurfaceDependencies& removed_dependencies) = 0;
+      const base::flat_set<SurfaceId>& added_dependencies,
+      const base::flat_set<SurfaceId>& removed_dependencies) = 0;
 
   // Called when |surface| is being destroyed.
   virtual void OnSurfaceDiscarded(Surface* surface) = 0;

cc/surfaces/surface.cc

@@ -220,13 +220,13 @@ void Surface::UpdateBlockingSurfaces(bool has_previous_pending_frame,
   // changes in dependencies so that we can update the SurfaceDependencyTracker
   // map.
   if (has_previous_pending_frame) {
-    SurfaceDependencies removed_dependencies;
+    base::flat_set<SurfaceId> removed_dependencies;
     for (const SurfaceId& surface_id : blocking_surfaces_) {
       if (!new_blocking_surfaces.count(surface_id))
         removed_dependencies.insert(surface_id);
     }
 
-    SurfaceDependencies added_dependencies;
+    base::flat_set<SurfaceId> added_dependencies;
     for (const SurfaceId& surface_id : new_blocking_surfaces) {
       if (!blocking_surfaces_.count(surface_id))
         added_dependencies.insert(surface_id);

cc/surfaces/surface.h

@@ -114,7 +114,7 @@ class CC_SURFACES_EXPORT Surface {
                : nullptr;
   }
 
-  const SurfaceDependencies& blocking_surfaces() const {
+  const base::flat_set<SurfaceId>& blocking_surfaces() const {
     return blocking_surfaces_;
   }
 
@@ -163,7 +163,7 @@ class CC_SURFACES_EXPORT Surface {
   bool destroyed_;
   std::vector<SurfaceSequence> destruction_dependencies_;
 
-  SurfaceDependencies blocking_surfaces_;
+  base::flat_set<SurfaceId> blocking_surfaces_;
   base::ObserverList<PendingFrameObserver, true> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(Surface);

cc/surfaces/surface_dependency_tracker.cc

@@ -159,8 +159,8 @@ void SurfaceDependencyTracker::OnSurfaceActivated(Surface* surface) {
 
 void SurfaceDependencyTracker::OnSurfaceDependenciesChanged(
     Surface* surface,
-    const SurfaceDependencies& added_dependencies,
-    const SurfaceDependencies& removed_dependencies) {
+    const base::flat_set<SurfaceId>& added_dependencies,
+    const base::flat_set<SurfaceId>& removed_dependencies) {
   // Update the |blocked_surfaces_from_dependency_| map with the changes in
   // dependencies.
   for (const SurfaceId& surface_id : added_dependencies)

cc/surfaces/surface_dependency_tracker.h

@@ -53,8 +53,8 @@ class CC_SURFACES_EXPORT SurfaceDependencyTracker : public BeginFrameObserver,
   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:

cc/surfaces/surface_factory.cc

@@ -128,8 +128,8 @@ void SurfaceFactory::OnSurfaceActivated(Surface* surface) {
 
 void SurfaceFactory::OnSurfaceDependenciesChanged(
     Surface* surface,
-    const SurfaceDependencies& added_dependencies,
-    const SurfaceDependencies& removed_dependencies) {}
+    const base::flat_set<SurfaceId>& added_dependencies,
+    const base::flat_set<SurfaceId>& removed_dependencies) {}
 
 void SurfaceFactory::OnSurfaceDiscarded(Surface* surface) {}
 

cc/surfaces/surface_factory.h

@@ -86,8 +86,8 @@ class CC_SURFACES_EXPORT SurfaceFactory : public PendingFrameObserver {
   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;
 
   std::unique_ptr<Surface> Create(const LocalSurfaceId& local_surface_id);