MultitouchMouseInterpreter: Initialized member variables

BUG=chromium:435688
TEST=able to update gtest. unittests aren't flakey

Change-Id: Iaae40a172ee83989b9d709e6d6425e261271546c
Reviewed-on: https://chromium-review.googlesource.com/231395
Reviewed-by: Alex Deymo <deymo@chromium.org>
Tested-by: Alex Deymo <deymo@chromium.org>
Commit-Queue: Alex Deymo <deymo@chromium.org>
diff --git a/include/multitouch_mouse_interpreter.h b/include/multitouch_mouse_interpreter.h
index 048e8e5..e38ccd0 100755
--- a/include/multitouch_mouse_interpreter.h
+++ b/include/multitouch_mouse_interpreter.h
@@ -25,9 +25,9 @@
   stime_t ButtonGoingUp(int button) const;
 
  private:
-  stime_t button_going_up_left_;
-  stime_t button_going_up_middle_;
-  stime_t button_going_up_right_;
+  stime_t button_going_up_left_{0.0};
+  stime_t button_going_up_middle_{0.0};
+  stime_t button_going_up_right_{0.0};
 };
 
 class MultitouchMouseInterpreter : public MouseInterpreter {