Merge to M47: Change |CCodec_ScanlineDecoder::m_Pitch| to FX_DWORD

This matches the type of the corresponding |CFX_DIBSource::m_Pitch|,
where integer overflow is checked for FX_DWORD. This change is
propagated to many other places.

Also, check for integer overflow in |CCodec_RLScanlineDecoder::Create|
during the calculation of |m_Pitch| since it aligns to 4 bytes while
overflow was was previously checked without this alignment.

TBR=thestig@chromium.org
BUG=555784

Original Review URL: https://codereview.chromium.org/1460033002 .

(cherry picked from commit e7950df70a2fd658f466751b29483436cb31e829)

Review URL: https://codereview.chromium.org/1473143003 .
5 files changed