Split toolchain update and install lookup to make generation faster

DEPS

 # This file is automatically processed to create .DEPS.git which is the file
 # that gclient uses under git.
 #
 # See http://code.google.com/p/chromium/wiki/UsingGit
 #
 # To test manually, run:
 #   python tools/deps2git/deps2git.py -o .DEPS.git
 #   gclient runhooks
 # DO NOT CHECK IN CHANGES TO .DEPS.git. It will be automatically updated by
 # a bot when you modify this one.
@@ skipping 619 matching lines @@
         "--linux-only",
         "--arch=i386"],
   },
   {
     # Pull clang if on Mac or clang is requested via GYP_DEFINES.
     "name": "clang",
     "pattern": ".",
     "action": ["python", "src/tools/clang/scripts/update.py", "--if-needed"],
   },
   {
+    # Update the Windows toolchain if necessary.
+    "name": "win_toolchain",
+    "pattern": ".",
+    "action": ["python", "src/build/vs_toolchain.py", "update"],
+  },
+  {
     # Update LASTCHANGE. This is also run by export_tarball.py in
     # src/tools/export_tarball - please keep them in sync.
     "name": "lastchange",
     "pattern": ".",
     "action": ["python", "src/build/util/lastchange.py",
                "-o", "src/build/util/LASTCHANGE"],
   },
   {
     # Update LASTCHANGE.blink. This is also run by export_tarball.py in
     # src/tools/export_tarball - please keep them in sync.
@@ skipping 105 matching lines @@
                 "-s", "src/build/linux/bin/eu-strip.sha1",
     ],
   },
   {
     # A change to a .gyp, .gypi, or to GYP itself should run the generator.
     "name": "gyp",
     "pattern": ".",
     "action": ["python", "src/build/gyp_chromium"],
   },
 ]