Mostly automatic incremental link enabling

Patch and tool to make turning on incremental linking on Windows easy.

BUG=94837
TEST=No link errors


Review URL: http://codereview.chromium.org/8059024

git-svn-id: http://src.chromium.org/svn/trunk/src/build@103474 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

common.gypi

@@ -436,7 +436,7 @@
 
     # Turn on Use Library Dependency Inputs for linking chrome.dll on Windows
     # to get incremental linking to be faster in debug builds.
-    'incremental_chrome_dll%': 0,
+    'incremental_chrome_dll%': '<!(python <(DEPTH)/tools/win/supalink/check_installed.py)',
 
     # This is the location of the sandbox binary. Chrome looks for this before
     # running the zygote process. If found, and SUID, it will be used to