There are a few bugs being fixed since we last took this file
Created attachment 170284 [details] Patch
Ken, please have a look. I made minimum modifications (only the absolutely necessary ones) to the original file: see the comments right after the copy right notice.
Attachment 170284 [details] did not pass style-queue: Source/WebCore/html/canvas/CheckedInt.h:15: #ifndef header guard has wrong style, please use: CheckedInt_h [build/header_guard] [5] Source/WebCore/html/canvas/CheckedInt.h:66: Missing space inside { }. [whitespace/braces] [5] Source/WebCore/html/canvas/CheckedInt.h:70: This { should be at the end of the previous line [whitespace/braces] [4] Source/WebCore/html/canvas/CheckedInt.h:76: This { should be at the end of the previous line [whitespace/braces] [4] Source/WebCore/html/canvas/CheckedInt.h:82: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:86: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:90: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:94: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:98: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:102: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:106: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:110: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:115: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:119: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:123: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:127: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:131: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:134: Omit int when using unsigned [runtime/unsigned] [1] Source/WebCore/html/canvas/CheckedInt.h:135: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:139: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:143: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:152: Missing space inside { }. [whitespace/braces] [5] Source/WebCore/html/canvas/CheckedInt.h:156: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:160: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:164: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:168: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:172: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:176: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:180: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:184: More than one command on the same line [whitespace/newline] [4] Source/WebCore/html/canvas/CheckedInt.h:188: This { should be at the end of the previous line [whitespace/braces] [4] Source/WebCore/html/canvas/CheckedInt.h:190: When wrapping a line, only indent 4 spaces. [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:195: This { should be at the end of the previous line [whitespace/braces] [4] Source/WebCore/html/canvas/CheckedInt.h:203: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:204: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:205: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:210: This { should be at the end of the previous line [whitespace/braces] [4] Source/WebCore/html/canvas/CheckedInt.h:216: This { should be at the end of the previous line [whitespace/braces] [4] Source/WebCore/html/canvas/CheckedInt.h:222: This { should be at the end of the previous line [whitespace/braces] [4] Source/WebCore/html/canvas/CheckedInt.h:223: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:227: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:242: This { should be at the end of the previous line [whitespace/braces] [4] Source/WebCore/html/canvas/CheckedInt.h:259: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:260: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:261: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:262: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:263: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:264: When wrapping a line, only indent 4 spaces. [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:273: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:277: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:278: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:279: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:281: This { should be at the end of the previous line [whitespace/braces] [4] Source/WebCore/html/canvas/CheckedInt.h:286: This { should be at the end of the previous line [whitespace/braces] [4] Source/WebCore/html/canvas/CheckedInt.h:292: This { should be at the end of the previous line [whitespace/braces] [4] Source/WebCore/html/canvas/CheckedInt.h:298: This { should be at the end of the previous line [whitespace/braces] [4] Source/WebCore/html/canvas/CheckedInt.h:303: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:304: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:305: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:306: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:307: Missing space inside { }. [whitespace/braces] [5] Source/WebCore/html/canvas/CheckedInt.h:311: This { should be at the end of the previous line [whitespace/braces] [4] Source/WebCore/html/canvas/CheckedInt.h:314: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:323: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:332: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:341: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:350: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:351: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:352: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:360: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:367: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:368: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:369: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:370: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:371: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:373: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:374: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:375: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:376: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:377: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:378: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:385: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:386: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:387: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:388: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:389: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:390: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:392: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:393: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:394: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:398: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:399: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:400: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:401: Missing space inside { }. [whitespace/braces] [5] Source/WebCore/html/canvas/CheckedInt.h:408: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:409: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:410: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:419: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:420: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:422: Tests for true/false, null/non-null, and zero/non-zero should all be done without equality comparisons. [readability/comparison_to_zero] [5] Source/WebCore/html/canvas/CheckedInt.h:422: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:425: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:427: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:428: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:429: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:431: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:432: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:433: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:434: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:443: Tests for true/false, null/non-null, and zero/non-zero should all be done without equality comparisons. [readability/comparison_to_zero] [5] Source/WebCore/html/canvas/CheckedInt.h:443: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:451: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:458: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:459: Boolean expressions that span multiple lines should have their operators on the left side of the line instead of the right side. [whitespace/operators] [4] Source/WebCore/html/canvas/CheckedInt.h:459: Tests for true/false, null/non-null, and zero/non-zero should all be done without equality comparisons. [readability/comparison_to_zero] [5] Source/WebCore/html/canvas/CheckedInt.h:459: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:460: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:466: This { should be at the end of the previous line [whitespace/braces] [4] Source/WebCore/html/canvas/CheckedInt.h:471: This { should be at the end of the previous line [whitespace/braces] [4] Source/WebCore/html/canvas/CheckedInt.h:478: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:558: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:565: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:566: When wrapping a line, only indent 4 spaces. [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:569: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:583: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:586: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:587: When wrapping a line, only indent 4 spaces. [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:593: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:594: When wrapping a line, only indent 4 spaces. [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:600: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:601: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:611: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:616: When wrapping a line, only indent 4 spaces. [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:621: When wrapping a line, only indent 4 spaces. [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:626: When wrapping a line, only indent 4 spaces. [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:631: When wrapping a line, only indent 4 spaces. [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:637: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:638: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:639: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:640: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:642: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:643: When wrapping a line, only indent 4 spaces. [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:644: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:667: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:673: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:674: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:680: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:681: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:682: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:688: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:689: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:695: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:696: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:697: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] Failed to run "['Tools/Scripts/check-webkit-style', '--diff-files', u'Source/WebCore/ChangeLog', u'Source/WebCor..." exit_code: 1 [3] Source/WebCore/html/canvas/CheckedInt.h:700: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:720: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:722: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:724: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:725: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:726: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:764: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:770: COMPOUND_OP is incorrectly named. Don't use underscores in your identifier names. [readability/naming/underscores] [4] Source/WebCore/html/canvas/CheckedInt.h:772: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:773: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:778: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:783: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:789: Missing spaces around / [whitespace/operators] [3] Source/WebCore/html/canvas/CheckedInt.h:797: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Source/WebCore/html/canvas/CheckedInt.h:804: Weird number of spaces at line-start. Are you using a 4-space indent? [whitespace/indent] [3] Total errors found: 169 in 6 files If any of these errors are false positives, please file a bug against check-webkit-style.
Built and tested with WebGL conformance tests 1.0.1 on Linux.
This update should allow you to significantly reduce your local diff, as we have moved to using stdint types instead of PR types. Also, we have fixed an important bug whereby we were relying on signed integer overflow being well-defined behavior, which it isn't. The new version runs without any errors reported by IOC (Integer Overflow Checker).
Comment on attachment 170284 [details] Patch Sounds fine; r=me. Assuming that this has been well tested by Mozilla too. Let's let the EWS test this on all platforms before landing.
http://hg.mozilla.org/mozilla-central/log/d3de9d8e2b5b/mfbt/CheckedInt.h shows that we haven't changed this file significantly since July 8, Bug 768538, which was released in Firefox 16, so it's already tested on our Release channel.
There's also http://hg.mozilla.org/mozilla-central/file/default/mfbt/tests/TestCheckedInt.cpp for a test for it -- pretty self-contained, you can probably shoehorn it into your test suites pretty easily.
Committed r132393: <http://trac.webkit.org/changeset/132393>