Define a single macro for enabling backup function.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 5b15e70db934c48f668345ed59f78af641f1d96f..d42a9687101944ea18b345c8c07b127a55b908db 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -418,6 +418,9 @@
       # Whether one-click signin is enabled or not.
       'enable_one_click_signin%': 0,
 
+      # Whether to back up data before sync.
+      'enable_pre_sync_backup%': 0,
+
       # Enable Chrome browser extensions
       'enable_extensions%': 1,
 
@@ -678,6 +681,7 @@
 
         ['OS=="win" or OS=="mac" or (OS=="linux" and chromeos==0)', {

[pvalenzuela1, 2014/06/19 00:15:58]

Based on the CL description (and the changes here), it appears this CL
purposefully does not fix the bug (check for iOS as the OS). Is this correct?

IMO we should make the fix as part of this CL.

[haitaol1, 2014/06/19 16:36:31]

Because there's only one OS variable, it can't be both mac and ios, so
(OS=="mac" and OS != "ios") is equivalent to OS=="mac". I think mac and ios are
probably mutual exclusive in this file. Can you patch this cl and run ios test
to verify?

On 2014/06/19 00:15:58, pvalenzuela1 wrote:

[pvalenzuela1, 2014/06/19 18:30:21]

Ah, you're right. I misread. This should work; you can set up an iOS environment
to confirm.

Please update the CL description to note that this disables the feature on iOS.
It is not clear from the code that it does this.

           'enable_one_click_signin%': 1,
+          'enable_pre_sync_backup%': 1,
         }],
 
         ['OS=="android"', {
@@ -1042,6 +1046,7 @@
     'use_third_party_translations%': '<(use_third_party_translations)',
     'remoting%': '<(remoting)',
     'enable_one_click_signin%': '<(enable_one_click_signin)',
+    'enable_pre_sync_backup%': '<(enable_pre_sync_backup)',
     'enable_webrtc%': '<(enable_webrtc)',
     'chromium_win_pch%': '<(chromium_win_pch)',
     'configuration_policy%': '<(configuration_policy)',
@@ -2459,6 +2464,9 @@
       ['enable_one_click_signin==1', {
         'defines': ['ENABLE_ONE_CLICK_SIGNIN'],
       }],
+      ['enable_pre_sync_backup==1', {
+        'defines': ['ENABLE_PRE_SYNC_BACKUP'],
+      }],
       ['use_xi2_mt!=0 and use_x11==1', {
         'defines': ['USE_XI2_MT=<(use_xi2_mt)'],
       }],