Fix heap-use-after-free in V8::Initialize()

Fix heap-use-after-free in V8::Initialize()

BUG=pdfium:376
R=tsepez@chromium.org

Committed: https://pdfium.googlesource.com/pdfium/+/ef86dcd61c4b42d3787638e6ec5b96d4d7b4167b

[jun_fang, 2016-02-02 11:55:18]

jun_fang@foxitsoftware.com changed reviewers:
+ thestig@chromium.org, tsepez@chromium.org

[jun_fang, 2016-02-02 11:55:18]

Hi Tom and Lei,

Please help to review this CL. Thanks!

[jun_fang, 2016-02-02 12:06:09]

https://codereview.chromium.org/1651193005/diff/20001/fpdfsdk/src/fpdfxfa/fpd...
File fpdfsdk/src/fpdfxfa/fpdfxfa_doc.cpp (left):

https://codereview.chromium.org/1651193005/diff/20001/fpdfsdk/src/fpdfxfa/fpd...
fpdfsdk/src/fpdfxfa/fpdfxfa_doc.cpp:1137: csContent = csContentC.GetPtr();
Here is the crashed point. 

FXSYS_wcslen was used to get the length of string. However, it relies
on whether the ending chars are "\0\0".  

const CFX_WideString& CFX_WideString::operator=(const FX_WCHAR* lpsz) {
  if (!lpsz || lpsz[0] == 0) {
    Empty();
  } else {
    AssignCopy(FXSYS_wcslen(lpsz), lpsz);
  }
  return *this;
}

[Tom Sepez, 2016-02-02 16:50:01]

lgtm

[jun_fang, 2016-02-03 01:35:44]

Description was changed from

==========
Fix heap-use-after-free in V8::Initialize()

BUG=pdfium:376
==========

to

==========
Fix heap-use-after-free in V8::Initialize()

BUG=pdfium:376
R=tsepez@chromium.org

Committed:
https://pdfium.googlesource.com/pdfium/+/ef86dcd61c4b42d3787638e6ec5b96d4d7b4...
==========

[jun_fang, 2016-02-03 01:35:48]

Committed patchset #2 (id:20001) manually as
ef86dcd61c4b42d3787638e6ec5b96d4d7b4167b (presubmit successful).