Bug 66311 – Chromium Mac: Fix implementation of wkScrollbarMinimumTotalLengthNeededForThumb to match WebKitSystemInterface

• Component: New Bugs
• Status: RESOLVED FIXED

[Sailesh Agrawal]

This bug is to track the work need to update wkScrollbarMinimumTotalLengthNeededForThumb() to match the implementation in WebKitSystemInterface.

[Sailesh Agrawal]

Created attachment 104139 [details]
Patch

[Nico Weber]

Comment on attachment 104139 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=104139&action=review

> Source/WebCore/platform/chromium/ScrollbarOverlayUtilitiesChromiumMac.mm:213
> +           [painter knobOverlapEndInset] +

why are trackOverlapEndInset and knobOverlapEndInset not *2?

[Sailesh Agrawal]

Comment on attachment 104139 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=104139&action=review

>> Source/WebCore/platform/chromium/ScrollbarOverlayUtilitiesChromiumMac.mm:213
>> +           [painter knobOverlapEndInset] +
> 
> why are trackOverlapEndInset and knobOverlapEndInset not *2?

I spent some time running this on Lion to see if I could figure out why the various values meant but I still don't understand it.

When I run this for opaque scrollbars I get the following values:
   - knobMinLenth: 20 
   - knobEndInset: 2
   - everything else: 0

For overlay scrollbars I get:
  - knowMinLength: 26
  - trackOverlapEndInset: 3
  - trackEndInset: 1

At this point I just gave up and copied the code from the disassembly.

[Sailesh Agrawal]

For reference, here's the disassembly:
http://code.google.com/p/chromium/issues/detail?id=74057#c35

and here's what I understood from it:

0xf0(%rbp) <- knobMinLength + trackOverlapEndInset + knobOverlapEndInset

0xe8(%rbp) <- trackEndInset
        movq        0x0010629d(%rip),%rsi         trackEndInset
        movq        %rbx,%rdi
        callq       0x00112d3e                    -[%rdi trackEndInset]
        movsd       %xmm0,0xe8(%rbp)

%xmm0 <- knobEndInset
        movq        0x00106281(%rip),%rsi         knobEndInset
        movq        %rbx,%rdi
        callq       0x00112d3e                    -[%rdi knobEndInset]

%xmm0 <- knobEndInset + trackEndInset
        addsd       0xe8(%rbp),%xmm0

%xmm0 <- (knobEndInset + trackEndInset) * 2
        addsd       %xmm0,%xmm0

%xmm0 <- knobMinLength + trackOverlapEndInset + knobOverlapEndInset + (knobEndInset + trackEndInset) * 2
        addsd       0xf0(%rbp),%xmm0

[Nico Weber]

Comment on attachment 104139 [details]
Patch

LGTM

[Dimitri Glazkov (Google)]

Comment on attachment 104139 [details]
Patch

my rubberstamp is quick like a monkey.

[WebKit Review Bot]

Comment on attachment 104139 [details]
Patch

Rejecting attachment 104139 [details] from commit-queue.

Failed to run "['./Tools/Scripts/webkit-patch', '--status-host=queues.webkit.org', '--bot-id=ec2-cq-02', '--port..." exit_code: 1

Last 500 characters of output:
it-commit-queue/LayoutTests/ChangeLog neither lists a valid reviewer nor contains the string "Unreviewed" or "Rubber stamp" (case insensitive).
Updating OpenSource
From git://git.webkit.org/WebKit
 + 0651a90...54d0520 master     -> origin/master  (forced update)
Current branch master is up to date.
Updating chromium port dependencies using gclient...

________ running '/usr/bin/python gyp_webkit' in '/mnt/git/webkit-commit-queue/Source/WebKit/chromium'
Updating webkit projects from gyp files...

Full output: http://queues.webkit.org/results/9403679

[Nico Weber]

Huh! If you reupload with `land-safely`, the script will hopefully fill in the "reviewed by" line; if not you'll have to do that manually. Weird the commit-queue didn't do that.

[Sailesh Agrawal]

Created attachment 104152 [details]
Patch for landing

[WebKit Review Bot]

Comment on attachment 104152 [details]
Patch for landing

Rejecting attachment 104152 [details] from commit-queue.

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[WebKit Review Bot]

Comment on attachment 104152 [details]
Patch for landing

Clearing flags on attachment: 104152

Committed r93202: <http://trac.webkit.org/changeset/93202>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.