Turn PCH on always for Windows now that 2008 is gone

It was already defaulted on for 2010, and as we no longer support 2008
clean this up. This has the side benefit of enabling pch for 2010e, which
was slightly incorrect in the previous "enable for 2010" case.

R=joi@chromium.org


Review URL: https://chromiumcodereview.appspot.com/11642028

git-svn-id: http://src.chromium.org/svn/trunk/src/build@174228 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

common.gypi

@@ -354,19 +354,11 @@
 
       # Use of precompiled headers on Windows.
       #
-      # This is on by default in VS 2010, but off by default for VS
-      # 2008 because of complications that it can cause with our
-      # trybots etc.
-      #
       # This variable may be explicitly set to 1 (enabled) or 0
       # (disabled) in ~/.gyp/include.gypi or via the GYP command line.
       # This setting will override the default.
       #
-      # Note that a setting of 1 is probably suitable for most or all
-      # Windows developers using VS 2008, since precompiled headers
-      # provide a build speedup of 20-25%.  There are a couple of
-      # small workarounds you may need to use when using VS 2008 (but
-      # not 2010), see
+      # See
       # http://code.google.com/p/chromium/wiki/WindowsPrecompiledHeaders
       # for details.
       'chromium_win_pch%': 0,
@@ -519,8 +511,8 @@
           'ui_compositor_image_transport%': 0,
         }],
 
-        # Turn precompiled headers on by default for VS 2010.
-        ['OS=="win" and MSVS_VERSION=="2010" and buildtype!="Official"', {
+        # Turn precompiled headers on by default.
+        ['OS=="win" and buildtype!="Official"', {
           'chromium_win_pch%': 1
         }],