cc: Support on demand raster with ganesh

cc/test/pixel_test.cc

Index: cc/test/pixel_test.cc
diff --git a/cc/test/pixel_test.cc b/cc/test/pixel_test.cc
index ae2e9984fdb9c1485015e2b976561aeae9142414..73abc1c3828bd6cda9eab556cda460fff187ea9e 100644
--- a/cc/test/pixel_test.cc
+++ b/cc/test/pixel_test.cc
@@ -15,6 +15,7 @@
 #include "cc/output/gl_renderer.h"
 #include "cc/output/output_surface_client.h"
 #include "cc/output/software_renderer.h"
+#include "cc/resources/raster_worker_pool.h"
 #include "cc/resources/resource_provider.h"
 #include "cc/resources/texture_mailbox_deleter.h"
 #include "cc/test/fake_output_surface_client.h"
@@ -146,6 +147,30 @@ void PixelTest::EnableExternalStencilTest() {
       ->set_has_external_stencil_test(true);
 }
 
+void PixelTest::RunOnDemandRasterTask(Task* on_demand_raster_task) {
+  TaskGraphRunner task_graph_runner;
+  NamespaceToken on_demand_task_namespace =
+      task_graph_runner.GetNamespaceToken();
+
+  // Construct a task graph that contains this single raster task.
+  TaskGraph graph;
+  graph.nodes.push_back(
+      TaskGraph::Node(on_demand_raster_task,
+                      RasterWorkerPool::kOnDemandRasterTaskPriority,
+                      0u));
+
+  // Schedule task and wait for task graph runner to finish running it.
+  task_graph_runner.ScheduleTasks(on_demand_task_namespace, &graph);
+  task_graph_runner.RunUntilIdle();
+
+  // Collect task now that it has finished running.
+  Task::Vector completed_tasks;
+  task_graph_runner.CollectCompletedTasks(on_demand_task_namespace,
+                                          &completed_tasks);
+  DCHECK_EQ(1u, completed_tasks.size());
+  DCHECK_EQ(completed_tasks[0], on_demand_raster_task);
+}
+
 void PixelTest::SetUpSoftwareRenderer() {
   scoped_ptr<SoftwareOutputDevice> device(new PixelTestSoftwareOutputDevice());
   output_surface_.reset(new PixelTestOutputSurface(device.Pass()));