Fix reference to timezone variable - removed in VS 2015

Fix reference to timezone variable - removed in VS 2015

It turns out that 'timezone' has been deprecated for a while. If
deprecation messages are enabled then VS 2013 says this when 'timezone'
is referenced:

warning C4996: 'timezone': This function or variable may be unsafe.
Consider using _get_timezone instead.

Sometimes features stay deprecated for decades, but in this case
'timezone' is now gone.

R=tsepez@chromium.org
BUG=440500
Committed: https://pdfium.googlesource.com/pdfium/+/cbcc7305fd8d0d0fbed316ed092642de10c3b207

[brucedawson, 2015-04-08 22:32:52]

brucedawson@chromium.org changed reviewers:
+ tsepez@chromium.org

[Tom Sepez, 2015-04-08 22:51:19]

https://codereview.chromium.org/1075673002/diff/1/fpdfsdk/src/jsapi/fxjs_v8.cpp
File fpdfsdk/src/jsapi/fxjs_v8.cpp (right):

https://codereview.chromium.org/1075673002/diff/1/fpdfsdk/src/jsapi/fxjs_v8.c...
fpdfsdk/src/jsapi/fxjs_v8.cpp:765: return (double)(-(timezone * 1000));
Is _get_timezone() defined on all of the VS versions we care about?  If so, can
we always use it, renaming |timezone| to avoid collisions?

Alternatively, I'd like to see a comment that timezone is a windows global,
since it looks undefined (and wrong) if the #if block isn't included.

[brucedawson, 2015-04-08 23:00:37]

Good questions. I know that _get_timezone() is defined in VS 2013, and MSDN
suggests that it is available as far back as VS 2005
(https://msdn.microsoft.com/en-us/library/38wx0s70(v=vs.80).aspx).

However I'm not sure about gcc and clang. A quick test suggests that they do not
support _get_timezone(), so at best we could wrap it in #ifdef _MSC_VER.
Thoughts?

timezone is confusing. I found it hard to figure out what was going on at first.
It is a global that is defined in <time.h>. Web searches are problematic. A
comment is reasonable enough since we are probably not the only persons who will
be confused when first hitting this.

[Tom Sepez, 2015-04-09 00:10:42]

On 2015/04/08 23:00:37, brucedawson wrote:
> Good questions. I know that _get_timezone() is defined in VS 2013, and MSDN
> suggests that it is available as far back as VS 2005
> (https://msdn.microsoft.com/en-us/library/38wx0s70(v=vs.80).aspx).
> 
> However I'm not sure about gcc and clang. A quick test suggests that they do
not
> support _get_timezone(), so at best we could wrap it in #ifdef _MSC_VER.
> Thoughts?
> 
> timezone is confusing. I found it hard to figure out what was going on at
first.
> It is a global that is defined in <time.h>. Web searches are problematic. A
> comment is reasonable enough since we are probably not the only persons who
will
> be confused when first hitting this.

LGTM once a comment is added.

[brucedawson, 2015-04-09 00:33:34]

Comment added.

[brucedawson, 2015-04-09 00:52:42]

The CQ bit was checked by brucedawson@chromium.org

[brucedawson, 2015-04-09 00:52:43]

The patchset sent to the CQ was uploaded after l-g-t-m from tsepez@chromium.org
Link to the patchset: https://codereview.chromium.org/1075673002/#ps20001
(title: "Adding explanatory comment.")

[commit-bot: I haz the power, 2015-04-09 00:57:36]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-04-09 00:57:37]

Commit queue rejected this change because it did not recognize the base URL.
Please commit your change manually.

[brucedawson, 2015-04-09 16:36:40]

Committed patchset #3 (id:40001) manually as
cbcc7305fd8d0d0fbed316ed092642de10c3b207 (presubmit successful).