gyp_chromium: Better parsing of -G command line flag.

build/gyp_chromium

Index: build/gyp_chromium
diff --git a/build/gyp_chromium b/build/gyp_chromium
index 11125751a0e5b0e515741ee8d18cd96c608a40e0..cd5cd43d3a6f6dd715d6829542111aec654b38fa 100755
--- a/build/gyp_chromium
+++ b/build/gyp_chromium
@@ -143,11 +143,26 @@ def GetOutputDirectory():
   """Returns the output directory that GYP will use."""
   # GYP generator flags from the command line. We can't use optparse since we
   # want to ignore all arguments other than "-G".

[scottmg, 2015/02/03 00:21:32]

I'm a little skeptical of this comment (though since you cc'd me, maybe I was
the author of it...)

Since the function's getting a bit long, could you do something like
http://stackoverflow.com/questions/1885161/how-can-i-get-optparses-optionpars...
instead to more closely match what gyp is going to do?

[Sam Clegg, 2015/02/03 01:20:10]

Done.

-  needle = '-Goutput_dir='
-  cmdline_input_items = []
+  flag = '-G'
+  found_flag = False
+  needle = 'output_dir='
   for item in sys.argv[1:]:
-    if item.startswith(needle):
-      return item[len(needle):]
+    if item == flag:
+      found_flag = True
+      continue
+
+    # Handle the two flag case (['-G', 'output_dir=foo'])
+    if found_flag:
+      found_flag = False
+      if item.startswith(needle):
+        return item[len(needle):]
+      continue
+
+    # Handle the single flag case (['-Goutput_dir=foo'])
+    if item.startswith(flag):
+      item = item[len(flag):]
+      if item.startswith(needle):
+        return item[len(needle):]
 
   env_items = shlex.split(os.environ.get('GYP_GENERATOR_FLAGS', ''))
   needle = 'output_dir='
@@ -155,7 +170,7 @@ def GetOutputDirectory():
     if item.startswith(needle):
       return item[len(needle):]
 
-  return "out"
+  return 'out'
 
 
 def additional_include_files(supplemental_files, args=[]):