Create a skeleton VisualDebugModule

BUG=skia:

Review URL: https://codereview.chromium.org/1498043002
diff --git a/tools/VisualBench/VisualDebugModule.h b/tools/VisualBench/VisualDebugModule.h
new file mode 100644
index 0000000..26385c3
--- /dev/null
+++ b/tools/VisualBench/VisualDebugModule.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef VisualDebugModule_DEFINED
+#define VisualDebugModule_DEFINED
+
+#include "VisualModule.h"
+
+#include "SkDebugCanvas.h"
+#include "VisualBench.h"
+#include "VisualBenchmarkStream.h"
+
+class VisualDebugModule : public VisualModule {
+public:
+    VisualDebugModule(VisualBench* owner);
+    void draw(SkCanvas* canvas) override;
+    bool onHandleChar(SkUnichar unichar) override;
+
+private:
+    enum State {
+        kInit_State,
+        kPlay_State,
+        kNext_State,
+    };
+
+    bool advanceIfNecessary(SkCanvas*);
+
+    State fState;
+    SkAutoTUnref<SkDebugCanvas> fDebugCanvas;
+    int fIndex;
+
+    // support framework
+    VisualBench* fOwner;
+    SkAutoTDelete<VisualBenchmarkStream> fBenchmarkStream;
+
+    typedef VisualModule INHERITED;
+};
+
+#endif