WIP GPU scheduler + delayed activation / tile draw

cc/resources/resource_provider.cc

Index: cc/resources/resource_provider.cc
diff --git a/cc/resources/resource_provider.cc b/cc/resources/resource_provider.cc
index 1be0b13564fc2774c44982e9f0bd6b967f5b2138..1fd797044fb0b4a3372e4ea078ec631a4c40fbc2 100644
--- a/cc/resources/resource_provider.cc
+++ b/cc/resources/resource_provider.cc
@@ -419,7 +419,8 @@ ResourceProvider::ResourceProvider(
       id_allocation_chunk_size_(id_allocation_chunk_size),
       use_sync_query_(false),
       buffer_to_texture_target_map_(buffer_to_texture_target_map),
-      tracing_id_(g_next_resource_provider_tracing_id.GetNext()) {
+      tracing_id_(g_next_resource_provider_tracing_id.GetNext()),
+      weak_ptr_factory_(this) {
   DCHECK(id_allocation_chunk_size_);
   DCHECK(thread_checker_.CalledOnValidThread());
 
@@ -944,6 +945,25 @@ void ResourceProvider::GenerateSyncTokenForResources(
   }
 }
 
+gpu::SyncToken ResourceProvider::GetSyncTokenForResource(
+    ResourceId resource_id) {
+  Resource* resource = GetResource(resource_id);
+  return resource->mailbox().sync_token();
+}
+
+gpu::SyncToken ResourceProvider::GetSyncTokenForResources(
+    const ResourceIdArray& resource_ids) {
+  gpu::SyncToken sync_token;
+  for (ResourceId id : resource_ids) {
+    Resource* resource = GetResource(id);
+    if (resource->mailbox().sync_token().release_count() >=
+        sync_token.release_count()) {
+      sync_token = resource->mailbox().sync_token();
+    }
+  }
+  return sync_token;
+}
+
 ResourceProvider::Resource* ResourceProvider::InsertResource(
     ResourceId id,
     Resource resource) {