create GYP files for these targets: tests, gm, skhello, skimage, skdiff

Created GYP files for remaining targets.
I have tested the following for each of these targets on Linux:

- Create and run makefile for each target independently
  ./gyp_skia tests.gyp && make
  out/Debug/tests

- Create makefile for all targets and build a single target
  ./gyp_skia && make tests
  out/Debug/tests

- Create makefile for and build all targets at once
  ./gyp_skia && make all
  out/Debug/tests

I have also generated Visual Studio (MSVS) projects for all targets and they look reasonable, but I haven't tried building them in Visual Studio yet.

I haven't tried to do anything with XCode targets yet.

[epoger, 2011-06-01 03:10:20]

+senorblanco

[bungeman, 2011-06-02 13:56:23]

On 2011/06/01 03:10:20, epoger wrote:
> +senorblanco

LGTM

[Stephen White, 2011-06-02 14:10:52]

LGTM.

http://codereview.appspot.com/4536096/diff/3001/gyp/bench.gyp
File gyp/bench.gyp (right):

http://codereview.appspot.com/4536096/diff/3001/gyp/bench.gyp#newcode4
gyp/bench.gyp:4: #  ./gyp_skia bench.gyp && make
Just out of curiosity, "./gyp_skia && make bench" should work as well, correct? 
(If/when we adopt gclient, gyp should run automatically and all you should have
to deal with is make).

http://codereview.appspot.com/4536096/diff/3001/gyp/images.gyp
File gyp/images.gyp (right):

http://codereview.appspot.com/4536096/diff/3001/gyp/images.gyp#newcode91
gyp/images.gyp:91: '../src/images/SkImageDecoder_libpng.cpp',
Are you sure 'sources' should be inside 'link_settings'?  Looks a little
strange.

http://codereview.appspot.com/4536096/diff/3001/gyp/tests.gyp
File gyp/tests.gyp (right):

http://codereview.appspot.com/4536096/diff/3001/gyp/tests.gyp#newcode15
gyp/tests.gyp:15: 'target_defaults.gypi',
Tangential to this CL, but it'd be nice if we could merge target_defaults.gypi
and common.gypi, since there's a lot of overlap.

[epoger, 2011-06-02 14:35:04]

Thanks, guys. Committing now.

http://codereview.appspot.com/4536096/diff/3001/gyp/bench.gyp
File gyp/bench.gyp (right):

http://codereview.appspot.com/4536096/diff/3001/gyp/bench.gyp#newcode4
gyp/bench.gyp:4: #  ./gyp_skia bench.gyp && make
On 2011/06/02 14:10:52, Stephen White wrote:
> Just out of curiosity, "./gyp_skia && make bench" should work as well,
correct? 
> (If/when we adopt gclient, gyp should run automatically and all you should
have
> to deal with is make).

Indeed you are correct.

While I have been working to make sure that the different gyp targets can be
generated independently, I think the common case will be as you describe
(generate all gyp targets, and then either "make" (same as "make all") or "make
<target>").

http://codereview.appspot.com/4536096/diff/3001/gyp/images.gyp
File gyp/images.gyp (right):

http://codereview.appspot.com/4536096/diff/3001/gyp/images.gyp#newcode91
gyp/images.gyp:91: '../src/images/SkImageDecoder_libpng.cpp',
On 2011/06/02 14:10:52, Stephen White wrote:
> Are you sure 'sources' should be inside 'link_settings'?  Looks a little
> strange.

It does look a bit strange but there is a good reason.  Added the following
comment:


            # Any targets that depend on this target should link in libpng and
            # our code that calls it.
            # See
http://code.google.com/p/gyp/wiki/InputFormatReference#Dependent_Settings

http://codereview.appspot.com/4536096/diff/3001/gyp/tests.gyp
File gyp/tests.gyp (right):

http://codereview.appspot.com/4536096/diff/3001/gyp/tests.gyp#newcode15
gyp/tests.gyp:15: 'target_defaults.gypi',
On 2011/06/02 14:10:52, Stephen White wrote:
> Tangential to this CL, but it'd be nice if we could merge target_defaults.gypi
> and common.gypi, since there's a lot of overlap.

Good idea; thanks for mentioning it.  I have made a note to try to do that in a
separate CL.

[epoger, 2011-06-02 14:39:51]

committed as r1479