Clarify warning for GYP variable merging.

Clarify warning for GYP variable merging.

https://codereview.chromium.org/931643002 changed variable merging
behavior for environment variables and chromium.gyp_env. The new
behavior replaces variables, with the exception of GYP_DEFINES
which is instead concatenated.

This change clarifies the state of the variables to the developer
by printing values, and more accurately describes the override
behavior as 'merges with, and individual components override,'.

Committed: https://crrev.com/eedc9ac929470feba9b8b4899c1aad14cbb5b97b
Cr-Commit-Position: refs/heads/master@{#320609}

[scheib, 2015-03-10 22:32:48]

scheib@chromium.org changed reviewers:
+ dongseong.hwang@intel.com

[scheib, 2015-03-13 22:39:07]

scheib@chromium.org changed reviewers:
+ scottmg@chromium.org
- dongseong.hwang@intel.com

[scottmg, 2015-03-13 23:05:46]

lgtm

https://codereview.chromium.org/993143002/diff/1/build/gyp_helper.py
File build/gyp_helper.py (right):

https://codereview.chromium.org/993143002/diff/1/build/gyp_helper.py#newcode54
build/gyp_helper.py:54: string_padding = max(len(var), len(file_path),
len("result"))
' not "

[scheib, 2015-03-13 23:09:48]

The CQ bit was checked by scheib@chromium.org

[scheib, 2015-03-13 23:09:48]

The patchset sent to the CQ was uploaded after l-g-t-m from scottmg@chromium.org
Link to the patchset: https://codereview.chromium.org/993143002/#ps20001 (title:
"' not "")

[scheib, 2015-03-13 23:10:18]

https://codereview.chromium.org/993143002/diff/1/build/gyp_helper.py
File build/gyp_helper.py (right):

https://codereview.chromium.org/993143002/diff/1/build/gyp_helper.py#newcode54
build/gyp_helper.py:54: string_padding = max(len(var), len(file_path),
len("result"))
On 2015/03/13 23:05:45, scottmg wrote:
> ' not "

Done.

[commit-bot: I haz the power, 2015-03-13 23:10:21]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/993143002/20001

[scheib, 2015-03-13 23:10:46]

The CQ bit was unchecked by scheib@chromium.org

[scheib, 2015-03-13 23:11:59]

The CQ bit was checked by scheib@chromium.org

[scheib, 2015-03-13 23:12:00]

The patchset sent to the CQ was uploaded after l-g-t-m from scottmg@chromium.org
Link to the patchset: https://codereview.chromium.org/993143002/#ps40001 (title:
"' not "")

[scheib, 2015-03-13 23:12:13]

Patchset #2 (id:20001) has been deleted

[commit-bot: I haz the power, 2015-03-13 23:12:49]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/993143002/40001

[commit-bot: I haz the power, 2015-03-14 00:14:09]

Committed patchset #2 (id:40001)

[commit-bot: I haz the power, 2015-03-14 00:15:01]

Patchset 2 (id:??) landed as
https://crrev.com/eedc9ac929470feba9b8b4899c1aad14cbb5b97b
Cr-Commit-Position: refs/heads/master@{#320609}