allow GMs to animate

samplecode/SampleCode.h

Index: samplecode/SampleCode.h
diff --git a/samplecode/SampleCode.h b/samplecode/SampleCode.h
index d09022f35064c877eb3d4ee4fe6d1b95343e037c..2912e81a9dcd7c8566da04c3883a922e36791158 100644
--- a/samplecode/SampleCode.h
+++ b/samplecode/SampleCode.h
@@ -117,6 +117,7 @@ public:
     {}
 
     void setBGColor(SkColor color) { fBGColor = color; }
+    bool animatePulse(SkMSec time) { return this->onAnimatePulse(time); }
 
     static bool IsSampleView(SkView*);
     static bool SetRepeatDraw(SkView*, int count);
@@ -136,6 +137,7 @@ public:
 protected:
     virtual void onDrawBackground(SkCanvas*);
     virtual void onDrawContent(SkCanvas*) = 0;
+    virtual bool onAnimatePulse(SkMSec) { return false; }
 
     // overrides
     virtual bool onEvent(const SkEvent& evt);