Adding cr application context class.

BUG=316397

Review URL: https://codereview.chromium.org/70693002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235635 0039d316-1c4b-4281-b951-d872f2087c98
Currently the design of conflict dialog box is not consistent with other dialog
boxes in Files.app.

This CL update the design for consistency.

BUG=317925
TEST=manually

Review URL: https://codereview.chromium.org/70783002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235636 0039d316-1c4b-4281-b951-d872f2087c98
[Downloads] Perform file existence check on blocking pool.

When the downloads history is loaded, each completed download in history
is checked to see if the target path still exists. This verification was
being performed on the FILE thread, which blocked other users of the
FILE thread including any active downloads. This change is to perform
the file existence check on the blocking pool instead. In addition, the
tasks are run sequentially so that a large download history doesn't
cause a large number of concurrent disk operations.

BUG=316152

Review URL: https://codereview.chromium.org/70803002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235637 0039d316-1c4b-4281-b951-d872f2087c98
Refactored the ComponentCloudPolicyService.

The ComponentCloudPolicyService is used to fetch cloud policy for components
of Chrome, such as extensions. This feature is currently disabled behind a
flag, on ChromeOS.

This refactor builds on recent changes to the policy code that make it possible
to significantly simplify this code:

- the list of components now comes from a SchemaRegistry
- all the dependencies come in the constructor (no more late Connect())
- cancel pending updates when components change

This is still a WIP; the next step is to make the ComponentCloudPolicyService
a PKS and decouple it from the UserCloudPolicyManagerChromeOS.

BUG=108992

Review URL: https://codereview.chromium.org/70863002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235638 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235638