GN: get echo-headers sources via exec_script

gyp/tests.gypi

 # Copyright 2015 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 # Common gypi for unit tests.
 {
   'include_dirs': [
     '../include/private',
     '../src/codec',
     '../src/core',
@@ skipping 17 matching lines @@
     'tools.gyp:sk_tool_utils',
     'zlib.gyp:zlib',
   ],
   'conditions': [
     [ 'skia_os not in ["linux", "freebsd", "openbsd", "solaris", "android"]', {
         'sources!': [ '../tests/FontMgrAndroidParserTest.cpp', ],
     }],
     [ 'not skia_pdf', {
       'dependencies!': [ 'pdf.gyp:pdf', 'zlib.gyp:zlib' ],
       'dependencies': [ 'pdf.gyp:nopdf' ],
-      'sources!': [ '<!@(python find.py ../tests "PDF*.c*")', ],
+      'sources!': [ '<!@(python find.py "PDF*.c*" ../tests)', ],
     }],
     [ 'skia_gpu_extra_tests_path', {
       'sources': [
-        '<!@(python find.py <(skia_gpu_extra_tests_path) "*.c*")',
+        '<!@(python find.py "*.c*" <(skia_gpu_extra_tests_path))',
       ],
     }],
   ],
   'sources': [
     '../tests/Test.h',
-    '<!@(python find.py ../tests "*.c*")',
+    '<!@(python find.py "*.c*" ../tests)',
     '../tools/debugger/SkDrawCommand.h',
     '../tools/debugger/SkDrawCommand.cpp',
     '../tools/debugger/SkDebugCanvas.h',
     '../tools/debugger/SkDebugCanvas.cpp',
     '../tools/debugger/SkJsonWriteBuffer.h',
     '../tools/debugger/SkJsonWriteBuffer.cpp',
     '../tools/debugger/SkObjectParser.h',
     '../tools/debugger/SkObjectParser.cpp',
     '../tools/debugger/SkOverdrawMode.h',
     '../tools/debugger/SkOverdrawMode.cpp',
   ],
   'sources!': [
     '../tests/SkpSkGrTest.cpp',
     '../tests/skia_test.cpp',
     '../tests/PathOpsAngleIdeas.cpp',
     '../tests/PathOpsBattles.cpp',
     '../tests/PathOpsCubicLineIntersectionIdeas.cpp',
     '../tests/PathOpsDebug.cpp',
     '../tests/PathOpsOpLoopThreadedTest.cpp',
     '../tests/PathOpsSkpClipTest.cpp',
   ],
 }