cc: Plumbing for BeginFrameSource based on Surfaces

cc/surfaces/surface.h

Index: cc/surfaces/surface.h
diff --git a/cc/surfaces/surface.h b/cc/surfaces/surface.h
index 8ef332ecb79756735b8f6760d23b34d954d973cd..56744ae9e1bdf7304d70e6d0519b5e18b90872f4 100644
--- a/cc/surfaces/surface.h
+++ b/cc/surfaces/surface.h
@@ -80,6 +80,27 @@ class CC_SURFACES_EXPORT Surface {
   bool destroyed() const { return destroyed_; }
   void set_destroyed(bool destroyed) { destroyed_ = destroyed; }
 
+  void AddDisplay(Display* display) {

[jbauman, 2015/09/04 23:58:36]

Probably best to use BeginFrameSource* everywhere here.

+    if (!base::ContainsValue(currently_displayed_on_,  display)) {

[jbauman, 2015/09/04 23:58:36]

DCHECK this?

+      currently_displayed_on_.push_back(display);
+      factory_->client()->SetBeginFrameSource(surface_id_, static_cast<BeginFrameSource*>(getPrimaryDisplay()));

[jbauman, 2015/09/04 23:58:36]

Be careful, as factory_ can be an invalidated weak pointer if the factory has
been destroyed.

Also, we should have factory destruction reset the BeginFrameSource for its
client.

+    }
+  }
+
+  void RemoveDisplay(Display* display) {
+    DCHECK(base::ContainsValue(current_displayed_on_,  display));
+
+    base::RemoveValue(current_displayed_on_, display);
+
+    factory_->client()->SetBeginFrameSource(surface_id_, static_cast<BeginFrameSource*>(getPrimaryDisplay()));
+  }
+
+  Display* getPrimaryDisplay() {
+    if (currently_displayed_on_.empty())
+      return NULL;
+    return current_displayed_on_[0];
+  }
+
  private:
   void ClearCopyRequests();
 
@@ -91,6 +112,7 @@ class CC_SURFACES_EXPORT Surface {
   bool destroyed_;
   std::vector<SurfaceSequence> destruction_dependencies_;
 
+  std::vector<Display*> currently_displayed_on_;
   std::vector<SurfaceId> referenced_surfaces_;
 
   DrawCallback draw_callback_;