Fix error handling in OpenProcess wrappers.  OpenProcess returns NULL on error, see http://msdn.microsoft.com/en-us/library/windows/desktop/ms684320(v=vs.85).aspx
Fix error handling in OpenProcess wrappers. 
OpenProcess returns NULL on error, see http://msdn.microsoft.com/en-us/library/windows/desktop/ms684320(v=vs.85).aspx

BUG= none
TEST= none

Review URL: http://codereview.chromium.org/9703019

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@126717 0039d316-1c4b-4281-b951-d872f2087c98

gavinp/chromium,yitian134/chromium,ropik/chromium,adobe/chromium,ropik/chromium,gavinp/chromium,ropik/chromium,adobe/chromium,yitian134/chromium,yitian134/chromium,adobe/chromium,yitian134/chromium,adobe/chromium,gavinp/chromium,gavinp/chromium,gavinp/chromium,adobe/chromium,yitian134/chromium,yitian134/chromium,ropik/chromium,adobe/chromium,yitian134/chromium,gavinp/chromium,ropik/chromium,adobe/chromium,ropik/chromium,adobe/chromium,adobe/chromium,yitian134/chromium,ropik/chromium,ropik/chromium,yitian134/chromium,adobe/chromium,gavinp/chromium,yitian134/chromium,adobe/chromium,ropik/chromium,gavinp/chromium,gavinp/chromium,gavinp/chromium