IDL compiler: [CallWith=ScriptState] with non-void return

This is primarily refactoring to correctly handle void return types;
properly need to consider |cpp_value| and |cpp_method| separately.

Also use |result| temporary variable, but only for
[CallWith=ScriptState] and [RaisesException] (to come);
much less common than for attributes, so simpler implementation
(without |cpp_original_value|).

BUG=239771
NOTRY=true

Review URL: https://codereview.chromium.org/60323004

git-svn-id: svn://svn.chromium.org/blink/trunk@161440 bbb929c8-8fbe-4397-9dbb-9b2b20218538
IDL compiler: Cleanup v8_utilities.py

Misc cleanup (noticed while implementing [DeprecatedAs],
split into separate CL).
* Remove unnecessary 'generate_' prefix
* Return a value instead of modifying |contents|
* Group functions by use
* Consistently use |extended_attributes| local variable
* Sort by Extended Attribute name
* Update docs
* Remove unnecessary |set()|

BUG=239771
NOTRY=true

Review URL: https://codereview.chromium.org/59853004

git-svn-id: svn://svn.chromium.org/blink/trunk@161441 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Auto-rebaseline for r161436

http://src.chromium.org/viewvc/blink?view=revision&revision=161436

TBR=g.czajkowski@samsung.com

Review URL: https://codereview.chromium.org/61773003

git-svn-id: svn://svn.chromium.org/blink/trunk@161444 bbb929c8-8fbe-4397-9dbb-9b2b20218538