Clarify components/README about when to create a component.

Clarify components/README about when to create a component.

BUG=624590
Committed: https://crrev.com/77c81222036bb21896fdec81724a154884c98f42
Cr-Commit-Position: refs/heads/master@{#407075}

[jam, 2016-07-20 20:53:20]

Patchset #1 (id:1) has been deleted

[jam, 2016-07-20 20:53:38]

jam@chromium.org changed reviewers:
+ blundell@chromium.org

[jam, 2016-07-20 21:17:00]

The CQ bit was checked by jam@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-07-20 21:17:21]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-07-20 22:05:08]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-07-20 22:05:08]

Dry run: This issue passed the CQ dry run.

[blundell, 2016-07-21 08:46:56]

Thanks, John!

https://codereview.chromium.org/2166093002/diff/20001/components/README
File components/README (right):

https://codereview.chromium.org/2166093002/diff/20001/components/README#newcode6
components/README:6: -code that is shared between Blink and the browser process
(since code in the
It looks like //content/browser includes lots of stuff from
//third_party/WebKit. Are those all problematic inclusions?

Until recently, //content couldn't depend on //components at all. Now that
Mandoline doesn't exist, what is the use case for having //content depend on
//components? 

(I know we had similar discussions recently, but the current and intended
dependency structure between //components, //content, and //third_party/WebKit
is still not clear in my head after those discussions).

https://codereview.chromium.org/2166093002/diff/20001/components/README#newco...
components/README:10: In general, if some code is used by component "foo" and
things above "foo" in
I find this comment ambiguous: when you say 'component "foo"', do you mean in
the sense of //components/foo or do you mean 'component' in a more general
sense? I'm not sure what this is intended to clarify given the quite concrete
guidelines you're adding above.

[jam, 2016-07-21 15:19:59]

https://codereview.chromium.org/2166093002/diff/20001/components/README
File components/README (right):

https://codereview.chromium.org/2166093002/diff/20001/components/README#newcode6
components/README:6: -code that is shared between Blink and the browser process
(since code in the
On 2016/07/21 08:46:56, blundell wrote:
> It looks like //content/browser includes lots of stuff from
> //third_party/WebKit. Are those all problematic inclusions?

Those are fine. We can include POD structs that are sent over IPC say. Also
enums and definitions of mojo interfaces. see comment in
https://cs.chromium.org/chromium/src/content/browser/DEPS?rcl=0&l=51

The main point is that we don't run WebKit there. This saves us from loading
chrome_child.dll in the browser process.

> 
> Until recently, //content couldn't depend on //components at all. Now that
> Mandoline doesn't exist, what is the use case for having //content depend on
> //components? 

There's an updated comment in
https://cs.chromium.org/chromium/src/content/DEPS?rcl=0&l=24, does that help?

Basically as we create generic mojo services, content can depend on them. this
is a step the demodularization of content. as an example, content can depend on
the generic leveldb service which is what the the new localstorage
implementation is built upon.

> 
> (I know we had similar discussions recently, but the current and intended
> dependency structure between //components, //content, and //third_party/WebKit
> is still not clear in my head after those discussions).

https://codereview.chromium.org/2166093002/diff/20001/components/README#newco...
components/README:10: In general, if some code is used by component "foo" and
things above "foo" in
On 2016/07/21 08:46:56, blundell wrote:
> I find this comment ambiguous: when you say 'component "foo"', do you mean in
> the sense of //components/foo or do you mean 'component' in a more general
> sense? I'm not sure what this is intended to clarify given the quite concrete
> guidelines you're adding above.

I meant in a general sense.

[jam, 2016-07-21 15:23:09]

https://codereview.chromium.org/2166093002/diff/20001/components/README
File components/README (right):

https://codereview.chromium.org/2166093002/diff/20001/components/README#newco...
components/README:10: In general, if some code is used by component "foo" and
things above "foo" in
On 2016/07/21 15:19:59, jam wrote:
> On 2016/07/21 08:46:56, blundell wrote:
> > I find this comment ambiguous: when you say 'component "foo"', do you mean
in
> > the sense of //components/foo or do you mean 'component' in a more general
> > sense? I'm not sure what this is intended to clarify given the quite
concrete
> > guidelines you're adding above.
> 
> I meant in a general sense.

I renamed this from "component" to directory, to make it less ambiguous.

[jam, 2016-07-21 15:23:51]

The CQ bit was checked by jam@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-07-21 15:24:04]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-07-21 16:00:36]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-07-21 16:00:37]

Dry run: This issue passed the CQ dry run.

[blundell, 2016-07-22 05:46:39]

LGTM, thanks!

[blundell, 2016-07-22 05:46:53]

The CQ bit was checked by blundell@chromium.org

[commit-bot: I haz the power, 2016-07-22 05:47:07]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-07-22 05:50:37]

Committed patchset #2 (id:40001)

[commit-bot: I haz the power, 2016-07-22 05:51:49]

Description was changed from

==========
Clarify components/README about when to create a component.

BUG=624590
==========

to

==========
Clarify components/README about when to create a component.

BUG=624590

Committed: https://crrev.com/77c81222036bb21896fdec81724a154884c98f42
Cr-Commit-Position: refs/heads/master@{#407075}
==========

[commit-bot: I haz the power, 2016-07-22 05:51:50]

Patchset 2 (id:??) landed as
https://crrev.com/77c81222036bb21896fdec81724a154884c98f42
Cr-Commit-Position: refs/heads/master@{#407075}