Enable forced extension updates on NaCl arch mismatch
This makes extensions aware of the platforms for which
they have platform-specific resources installed, if any.
This also hooks up the extension update code with some
additional logic to place an extension in forced-update
mode if it has platform-specific resources which don't
match the current NaCl architecture.
BUG=409948
TEST=install an extension which uses NaCl (QuickOffice for example). Rename the _platform-specific/<your-nacl-arch> directory some something else and force an update (e.g. via chrome://extensions button). Observe that a new CRX is downloaded and installed.
Review URL: https://codereview.chromium.org/516293007
7 files changed
