cc: Remove ScheduleOnOriginThread() and CompleteOnOriginThread().

cc/tiles/tile_manager_unittest.cc

Index: cc/tiles/tile_manager_unittest.cc
diff --git a/cc/tiles/tile_manager_unittest.cc b/cc/tiles/tile_manager_unittest.cc
index 7a121560cf877a55be6b7604f605a03098077b05..81d1d0c083a1f8f5fac756b1d5abeedda55afeb9 100644
--- a/cc/tiles/tile_manager_unittest.cc
+++ b/cc/tiles/tile_manager_unittest.cc
@@ -1835,7 +1835,7 @@ class FakeTileTaskRunner : public TileTaskRunner, public TileTaskClient {
 
   // TileTaskRunner methods.
   void Shutdown() override {}
-  void CheckForCompletedTasks() override {}
+  void CollectCompletedTasks(Task::Vector* completed_tasks) override {}
   ResourceFormat GetResourceFormat(bool must_support_alpha) const override {
     return ResourceFormat::RGBA_8888;
   }
@@ -1843,6 +1843,8 @@ class FakeTileTaskRunner : public TileTaskRunner, public TileTaskClient {
     return false;
   }
 
+  TileTaskClient* AsTileTaskClient() override { return this; }
+
   void ScheduleTasks(TaskGraph* graph) override {}
 
   // TileTaskClient methods.
@@ -1863,11 +1865,8 @@ class CancellingTileTaskRunner : public FakeTileTaskRunner {
   ~CancellingTileTaskRunner() override {}
 
   void ScheduleTasks(TaskGraph* graph) override {
-    // Just call CompleteOnOriginThread on each item in the queue. As none of
-    // these items have run yet, they will be treated as cancelled tasks.
-    for (const auto& node : graph->nodes) {
-      static_cast<TileTask*>(node.task)->CompleteOnOriginThread(this);
-    }
+    // Don't do anything. As none of these items have scheduled yet, they will
+    // be treated as cancelled tasks.
   }
 };
 
@@ -1939,15 +1938,7 @@ class VerifyResourceContentIdTileTaskRunner : public FakeTileTaskRunner {
       : expected_resource_id_(expected_resource_id) {}
   ~VerifyResourceContentIdTileTaskRunner() override {}
 
-  void ScheduleTasks(TaskGraph* graph) override {
-    for (const auto& node : graph->nodes) {
-      TileTask* task = static_cast<TileTask*>(node.task);
-      // Triggers a call to AcquireBufferForRaster.
-      task->ScheduleOnOriginThread(this);
-      // Calls TileManager as though task was cancelled.
-      task->CompleteOnOriginThread(this);
-    }
-  }
+  void ScheduleTasks(TaskGraph* graph) override {}
 
   // TileTaskClient methods.
   std::unique_ptr<RasterBuffer> AcquireBufferForRaster(