Files.app: Add ContentMetadataProvider class.

Files.app: Add ContentMetadataProvider class.

It provides metadata obtained from the content in SharedWorker.

BUG=410766
TEST=FileManagerJsTest.ContentMetadataProvider

Committed: https://crrev.com/ed42610fca4e196ae4a3c26c29f5dcfbaaa68231
Cr-Commit-Position: refs/heads/master@{#314512}

[hirono, 2015-02-04 04:38:30]

hirono@chromium.org changed reviewers:
+ yawano@chromium.org

[hirono, 2015-02-04 04:38:31]

PTAL, thanks! Almost all lines are copied from ContentProvider in
metadata_cache.js. I changed the following points.

* The name of class so that it consistent with FileSystemMetadataProvider and
ExternalProvider.
* Stop to build method name dynamically to make it @struct class. Instead it
uses a switch statement.
* It returns just thumbnailURL and thumbnailTransform.

[yawano, 2015-02-04 05:12:11]

https://codereview.chromium.org/894883003/diff/20001/ui/file_manager/file_man...
File
ui/file_manager/file_manager/foreground/js/metadata/content_metadata_provider.js
(right):

https://codereview.chromium.org/894883003/diff/20001/ui/file_manager/file_man...
ui/file_manager/file_manager/foreground/js/metadata/content_metadata_provider.js:14:
* @param {!MetadataProviderCache<!ContentMetadata>} cache
MetadataCacheSet does not have template variable.

https://codereview.chromium.org/894883003/diff/20001/ui/file_manager/file_man...
ui/file_manager/file_manager/foreground/js/metadata/content_metadata_provider.js:35:
opt_messagePort : new SharedWorker(ContentProvider.WORKER_SCRIPT).port;
ContentProvider.WORKER_SCRIPT -> ContentMetadataProvider.WORKER_SCRIPT?

https://codereview.chromium.org/894883003/diff/20001/ui/file_manager/file_man...
ui/file_manager/file_manager/foreground/js/metadata/content_metadata_provider.js:188:
metadata.thumbnailURL = '';
Is this error handling still necessary for new metadata provider?
NewMetadataProvider seems to become able to handle rejections of promises.

[hirono, 2015-02-04 05:38:40]

https://codereview.chromium.org/894883003/diff/20001/ui/file_manager/file_man...
File
ui/file_manager/file_manager/foreground/js/metadata/content_metadata_provider.js
(right):

https://codereview.chromium.org/894883003/diff/20001/ui/file_manager/file_man...
ui/file_manager/file_manager/foreground/js/metadata/content_metadata_provider.js:14:
* @param {!MetadataProviderCache<!ContentMetadata>} cache
On 2015/02/04 05:12:11, yawano wrote:
> MetadataCacheSet does not have template variable.

Done.

https://codereview.chromium.org/894883003/diff/20001/ui/file_manager/file_man...
ui/file_manager/file_manager/foreground/js/metadata/content_metadata_provider.js:35:
opt_messagePort : new SharedWorker(ContentProvider.WORKER_SCRIPT).port;
On 2015/02/04 05:12:11, yawano wrote:
> ContentProvider.WORKER_SCRIPT -> ContentMetadataProvider.WORKER_SCRIPT?

Done.

https://codereview.chromium.org/894883003/diff/20001/ui/file_manager/file_man...
ui/file_manager/file_manager/foreground/js/metadata/content_metadata_provider.js:188:
metadata.thumbnailURL = '';
On 2015/02/04 05:12:11, yawano wrote:
> Is this error handling still necessary for new metadata provider?
> NewMetadataProvider seems to become able to handle rejections of promises.

Done.

[yawano, 2015-02-04 05:48:50]

lgtm.

[hirono, 2015-02-04 06:05:14]

New patchsets have been uploaded after l-g-t-m from yawano@chromium.org

[hirono, 2015-02-04 06:05:48]

The CQ bit was checked by hirono@chromium.org

[commit-bot: I haz the power, 2015-02-04 06:06:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/894883003/60001

[commit-bot: I haz the power, 2015-02-04 06:40:48]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-02-04 06:42:00]

Patchset 4 (id:??) landed as
https://crrev.com/ed42610fca4e196ae4a3c26c29f5dcfbaaa68231
Cr-Commit-Position: refs/heads/master@{#314512}