Move CheckedInSdkPath helpers to utils

Move CheckedInSdkPath helpers to utils

BUG=
R=ricow@google.com

Committed: https://github.com/dart-lang/sdk/commit/28a223928924ff656be6e4fee466d34e41a29bf5

[Cutch, 2015-09-11 21:43:01]

johnmccutchan@google.com changed reviewers:
+ ricow@google.com

[ricow1, 2015-09-14 05:46:41]

lgtm

https://codereview.chromium.org/1342493003/diff/1/tools/utils.py
File tools/utils.py (right):

https://codereview.chromium.org/1342493003/diff/1/tools/utils.py#newcode19
tools/utils.py:19: SCRIPT_DIR = os.path.dirname(sys.argv[0])
we don't normally do this, see comment in function below

https://codereview.chromium.org/1342493003/diff/1/tools/utils.py#newcode599
tools/utils.py:599: osdict = {'Darwin':'mac', 'Linux':'linux', 'Windows':'win'}
please add a comment here:
# We don't use the normal macos/linux/win32 here. These are the
# prefixes that automatic platform checkouts in 
# download_from_google_storage is done

https://codereview.chromium.org/1342493003/diff/1/tools/utils.py#newcode606
tools/utils.py:606: return os.path.join(DART_ROOT,
This seems to work better in general
tools_dir = os.path.dirname(os.path.realpath(__file__))
return os.path.join(tools_dir, 'sdks', osname, 'dart-sdk'_

[Cutch, 2015-09-14 14:05:44]

https://codereview.chromium.org/1342493003/diff/1/tools/utils.py
File tools/utils.py (right):

https://codereview.chromium.org/1342493003/diff/1/tools/utils.py#newcode19
tools/utils.py:19: SCRIPT_DIR = os.path.dirname(sys.argv[0])
On 2015/09/14 05:46:41, ricow1 wrote:
> we don't normally do this, see comment in function below

Done.

https://codereview.chromium.org/1342493003/diff/1/tools/utils.py#newcode599
tools/utils.py:599: osdict = {'Darwin':'mac', 'Linux':'linux', 'Windows':'win'}
On 2015/09/14 05:46:41, ricow1 wrote:
> please add a comment here:
> # We don't use the normal macos/linux/win32 here. These are the
> # prefixes that automatic platform checkouts in 
> # download_from_google_storage is done

Done.

https://codereview.chromium.org/1342493003/diff/1/tools/utils.py#newcode606
tools/utils.py:606: return os.path.join(DART_ROOT,
On 2015/09/14 05:46:41, ricow1 wrote:
> This seems to work better in general
> tools_dir = os.path.dirname(os.path.realpath(__file__))
> return os.path.join(tools_dir, 'sdks', osname, 'dart-sdk'_

Done.

[Cutch, 2015-09-14 14:05:56]

Committed patchset #3 (id:40001) manually as
28a223928924ff656be6e4fee466d34e41a29bf5 (presubmit successful).