Add viewer mode to VisualBench.

Displays each benchmark/skp with a graph showing a series of frame times.
Use the space bar to skip to the next benchmark.

Adds an option to hit ESC to quit VisualBench. Useful in fullscreen mode.

Review URL: https://codereview.chromium.org/1336043003
diff --git a/tools/VisualBench/VisualModule.h b/tools/VisualBench/VisualModule.h
index ec4463d..2f83793 100644
--- a/tools/VisualBench/VisualModule.h
+++ b/tools/VisualBench/VisualModule.h
@@ -25,6 +25,8 @@
 
     virtual void draw(SkCanvas* canvas)=0;
 
+    virtual bool onHandleChar(SkUnichar unichar) = 0;
+
 private:
     typedef SkRefCnt INHERITED;
 };