Add a Display and ContextProvider concept to mojom, use to recreate

services/surfaces/surfaces_scheduler.cc

Index: services/surfaces/surfaces_scheduler.cc
diff --git a/services/surfaces/surfaces_scheduler.cc b/services/surfaces/surfaces_scheduler.cc
index 0d042949feed5b0e6a40aaa1beeacc4c5ade2c7a..63942dbcee9e37b812dc07c887a5f3573568091d 100644
--- a/services/surfaces/surfaces_scheduler.cc
+++ b/services/surfaces/surfaces_scheduler.cc
@@ -4,12 +4,11 @@
 
 #include "services/surfaces/surfaces_scheduler.h"
 
-namespace surfaces {
+#include "cc/surfaces/display.h"
 
-SurfacesScheduler::Client::~Client() {
-}
+namespace surfaces {
 
-SurfacesScheduler::SurfacesScheduler(Client* client) : client_(client) {
+SurfacesScheduler::SurfacesScheduler() {
   cc::SchedulerSettings settings;
   scheduler_ = cc::Scheduler::Create(
       this, settings, 0, base::MessageLoop::current()->task_runner(), nullptr,
@@ -32,6 +31,17 @@ void SurfacesScheduler::OnVSyncParametersUpdated(base::TimeTicks timebase,
   scheduler_->CommitVSyncParameters(timebase, interval);
 }
 
+void SurfacesScheduler::AddDisplay(cc::Display* display) {
+  DCHECK(displays_.find(display) == displays_.end());
+  displays_.insert(display);
+}
+
+void SurfacesScheduler::RemoveDisplay(cc::Display* display) {
+  auto it = displays_.find(display);
+  DCHECK(it != displays_.end());
+  displays_.erase(it);
+}
+
 void SurfacesScheduler::WillBeginImplFrame(const cc::BeginFrameArgs& args) {
 }
 
@@ -42,7 +52,9 @@ void SurfacesScheduler::ScheduledActionSendBeginMainFrame() {
 
 cc::DrawResult SurfacesScheduler::ScheduledActionDrawAndSwapIfPossible() {
   base::TimeTicks start = base::TimeTicks::Now();
-  client_->Draw();
+  for (const auto& it : displays_) {
+    it->Draw();
+  }
   base::TimeDelta duration = base::TimeTicks::Now() - start;
 
   draw_estimate_ = (duration + draw_estimate_) / 2;