tolerate a NULL hist being passed as a result of invalid parameters passed to init_rate_histogram(). this fixes a divide by zero in init_rate_histogram() with an invalid fps. BUG=webm:1383 Change-Id: Id203e0f3b18d67a4a09aaf206abcce4708f966ec
Change-Id: Ibd5395bf8956a80f7c0df4d539c7a42c927a1fc7
Change-Id: I05b7fb378b6b0c5f263e7839f96ba6830ee34fd2
Adding rate_hist.{h, c} files. Change-Id: Iaa28af6b25ec8982966a7296a073d6017b3a7f96