small tidy of benchmarkstream

BUG=skia:

Review URL: https://codereview.chromium.org/1395703002
diff --git a/tools/VisualBench/TimingStateMachine.cpp b/tools/VisualBench/TimingStateMachine.cpp
index ae03f5d..85aab42 100644
--- a/tools/VisualBench/TimingStateMachine.cpp
+++ b/tools/VisualBench/TimingStateMachine.cpp
@@ -91,9 +91,7 @@
     fLastMeasurement = this->elapsed() / (FLAGS_frames * fLoops);
 }
 
-void TimingStateMachine::nextBenchmark(SkCanvas* canvas, Benchmark* benchmark) {
-    benchmark->postDraw(canvas);
-    benchmark->perCanvasPostDraw(canvas);
+void TimingStateMachine::nextBenchmark() {
     fLoops = 1;
     fInnerState = kTuning_InnerState;
     fState = kPreWarm_State;