[NaCl SDK] Change KernelProxy::GetCWD() to allocate path.

When supplying a zero size to getcwd() typical behavior is to allocate
internally and return a pointer.  This behavior was already implemented, but
disabled by checking if size <= 0 and erroring with EINVAL.  As size_t is
positive definite, this entire check can be removed.

R=noelallen@chromium.org, sbc@chromium.org, binji@chromium.org
BUG=

Review URL: https://codereview.chromium.org/122943005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244213 0039d316-1c4b-4281-b951-d872f2087c98
BrowserPlugin: Minimize BrowserPluginEmbedder static casts

BUG=330843

Review URL: https://codereview.chromium.org/133013007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244214 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 244213
remove SK_SUPPORT_LEGACY_SK64, as all call-sites have been updated

BUG=

Review URL: https://codereview.chromium.org/133903003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244215 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 244215