Disk cache: Exclude file_posix from iOS.

There is a file_ios file already.

BUG=330074
R=stuartmorgan@chromium.org

Review URL: https://codereview.chromium.org/141693008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247386 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247386
Fix dangling pointer in Isolated FS MessageFilter

In CrxFs API, PepperIsolatedFileSystemMessageFilter used to
const-ref to BrowserPpapiHost via GetProfileDataDirectory.  But when
plugin is dead or dying, it's possible that BrowserPpapiHost has been
destroyed but MessageFilter is still alive, since the former is not
ref-counted.  When that happens, PepperIsolatedFileSystemMessageFilter
holds a dangling reference.

MessageFilter now stores profile directory itself.

TEST=out/Debug/browser_tests --gtest_filter="PPAPITest.*"
BUG=N/A

Review URL: https://codereview.chromium.org/147303002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247387 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247387