Fix the toolkit_views gyp variable define mania.

Fix the toolkit_views gyp variable define mania.

This makes it so toolkit_views==1 is always true for views builds,
either on Windows or ChromeOS.

Three levels of nesting are needed for this chained conditional:
1) Set the default value of ChromeOS.
2) Depending on ChromeOS value, set the default value of toolkit_views.
3) Depending on toolkit_views value, set the rest of the build variables.

This should have no affect on the build, but will allow subsequent cleanup.

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=45639

[Evan Martin, 2010-04-26 22:05:56]

This makes it so
  toolkit_views==1
is always true for views builds throughout gyp.
This will allow simplifying some other code.

http://build.chromium.org/buildbot/try-server/waterfall?branch=&committer=eva...
 (still running through trybots, had to fix one cros glitch so far)

[Evan Martin, 2010-04-26 22:06:59]

http://codereview.chromium.org/1799002/diff/4001/5001
File build/common.gypi (right):

http://codereview.chromium.org/1799002/diff/4001/5001#newcode53
build/common.gypi:53: # We set the initial value at this level of nesting so
it's available for
will fix before landing

[sky, 2010-04-26 22:35:55]

OK