Fix overflow when comparing two ints by promoting the sum to 64-bits.

R=reed@google.com, scroggo@google.com

Author: djsollen@google.com

Review URL: https://codereview.chromium.org/505153003

bug: 17265206
Change-Id: Id74fc6d165b55258dbd980d9d36afe1377e7a162
Prevent malformed ICO files from recursively decoding

R=reed@google.com, scroggo@google.com

Author: djsollen@google.com

Review URL: https://codereview.chromium.org/511453002

bug:17265466,17262540
Change-Id: I128b54c74d75b7afca20e47e6650c500278c5adc