Use paths relative to build dir in custom actions.

tools/gn/ninja_script_target_writer_unittest.cc

Index: tools/gn/ninja_script_target_writer_unittest.cc
diff --git a/tools/gn/ninja_script_target_writer_unittest.cc b/tools/gn/ninja_script_target_writer_unittest.cc
index 2057f072ce5582970c008f9f776dd48dca148935..a4ec87d6af22ac4271c5f05d0f252b5097bdfbd9 100644
--- a/tools/gn/ninja_script_target_writer_unittest.cc
+++ b/tools/gn/ninja_script_target_writer_unittest.cc
@@ -91,14 +91,14 @@ TEST(NinjaScriptTargetWriter, InvokeOverSources) {
 
     const char expected_linux[] =
         "rule __foo_bar___rule\n"
-        "  command = cd ../../foo; $pythonpath ../../foo/script.py -i ${source} \"--out=foo$ bar${source_name_part}.o\"\n"
+        "  command = $pythonpath ../../foo/script.py -i ${source} \"--out=foo$ bar${source_name_part}.o\"\n"

[brettw, 2013/10/23 16:27:05]

I guess you'll have to update this, maybe you'll need to explicitly set the
python path for the build above.

[koz (OOO until 15th September), 2013/10/24 05:56:28]

Done.

         "  description = CUSTOM //foo:bar()\n"
         "  restat = 1\n"
         "\n"
-        "build input1.out: __foo_bar___rule../../foo/input1.txt | ../../foo/included.txt\n"
+        "build input1.out: __foo_bar___rule ../../foo/input1.txt | ../../foo/included.txt\n"
         "  source = ../../foo/input1.txt\n"
         "  source_name_part = input1\n"
-        "build input2.out: __foo_bar___rule../../foo/input2.txt | ../../foo/included.txt\n"
+        "build input2.out: __foo_bar___rule ../../foo/input2.txt | ../../foo/included.txt\n"
         "  source = ../../foo/input2.txt\n"
         "  source_name_part = input2\n"
         "\n"
@@ -134,11 +134,11 @@ TEST(NinjaScriptTargetWriter, InvokeOverSources) {
         "  rspfile = __foo_bar___rule.$unique_name.rsp\n"
         "  rspfile_content = C:/python/python.exe ../../foo/script.py -i ${source} \"--out=foo$ bar${source_name_part}.o\"\n"
         "\n"
-        "build input1.out: __foo_bar___rule../../foo/input1.txt | ../../foo/included.txt\n"
+        "build input1.out: __foo_bar___rule ../../foo/input1.txt | ../../foo/included.txt\n"
         "  unique_name = 0\n"
         "  source = ../../foo/input1.txt\n"
         "  source_name_part = input1\n"
-        "build input2.out: __foo_bar___rule../../foo/input2.txt | ../../foo/included.txt\n"
+        "build input2.out: __foo_bar___rule ../../foo/input2.txt | ../../foo/included.txt\n"
         "  unique_name = 1\n"
         "  source = ../../foo/input2.txt\n"
         "  source_name_part = input2\n"