add SkAnimTimer, SPACE = pause/resume, ESP = stop

gm/gm.cpp

Index: gm/gm.cpp
diff --git a/gm/gm.cpp b/gm/gm.cpp
index c8109a7e2683e65745631e62eef8acfe3cfb3a01..8d269d977d88208da6987f53e342a87340b2e4a6 100644
--- a/gm/gm.cpp
+++ b/gm/gm.cpp
@@ -51,8 +51,8 @@ void GM::setBGColor(SkColor color) {
     fBGColor = color;
 }
 
-bool GM::animatePulse(SkMSec curr, SkMSec prev) {
-    return this->onAnimatePulse(curr, prev);
+bool GM::animate(const SkAnimTimer& timer) {
+    return this->onAnimate(timer);
 }
 
 /////////////////////////////////////////////////////////////////////////////////////////////