Attempt to reapply crrev.com/137083.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 3f3d972a95db4010ae5156241c1af24a3acdf6c3..365913b841f1c0c5390e3845ea01099fa9a92c75 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -52,6 +52,16 @@
           # Allows us to *temporarily* disable certain things for
           # staging.  Only set to 1 in a GYP_DEFINES.
           'android_upstream_bringup%': 0,
+
+          # Override buildtype to select the desired build flavor.
+          # Dev - everyday build for development/testing
+          # Official - release build (generally implies additional processing)
+          # TODO(mmoss) Once 'buildtype' is fully supported (e.g. Windows gyp
+          # conversion is done), some of the things which are now controlled by
+          # 'branding', such as symbol generation, will need to be refactored
+          # based on 'buildtype' (i.e. we don't care about saving symbols for
+          # non-Official # builds).
+          'buildtype%': 'Dev',
         },
         # Copy conditionally-set variables out one scope.
         'chromeos%': '<(chromeos)',
@@ -64,6 +74,10 @@
         'enable_touch_ui%': '<(enable_touch_ui)',
         'enable_metro%': '<(enable_metro)',
         'android_upstream_bringup%': '<(android_upstream_bringup)',
+        'buildtype%': '<(buildtype)',
+
+        # Use of precompiled headers on Windows. See comment below.
+        'chromium_win_pch%': '0',
 
         # Compute the architecture that we're building on.
         'conditions': [
@@ -126,6 +140,7 @@
       'enable_touch_ui%': '<(enable_touch_ui)',
       'enable_metro%': '<(enable_metro)',
       'android_upstream_bringup%': '<(android_upstream_bringup)',
+      'chromium_win_pch%': '<(chromium_win_pch)',
 
       # We used to provide a variable for changing how libraries were built.
       # This variable remains until we can clean up all the users.
@@ -137,15 +152,7 @@
       # Override branding to select the desired branding flavor.
       'branding%': 'Chromium',
 
-      # Override buildtype to select the desired build flavor.
-      # Dev - everyday build for development/testing
-      # Official - release build (generally implies additional processing)
-      # TODO(mmoss) Once 'buildtype' is fully supported (e.g. Windows gyp
-      # conversion is done), some of the things which are now controlled by
-      # 'branding', such as symbol generation, will need to be refactored based
-      # on 'buildtype' (i.e. we don't care about saving symbols for non-Official
-      # builds).
-      'buildtype%': 'Dev',
+      'buildtype%': '<(buildtype)',
 
       # Default architecture we're building for is the architecture we're
       # building on.
@@ -441,7 +448,7 @@
         }],
 
         # Turn precompiled headers on by default for VS 2010.
-        ['OS=="win" and MSVS_VERSION=="2010"', {
+        ['OS=="win" and MSVS_VERSION=="2010" and buildtype!="Official"', {
           'chromium_win_pch%': 1
         }],