Allow SessionService to be disabled.

chrome/chrome_browser.gypi

Index: chrome/chrome_browser.gypi
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index d263238504cc9b29a470bbe35992c0f50c06af80..3ea6095938fc9f92451ee2e269320ec401f3b0b6 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -4484,6 +4484,13 @@
             ['exclude', '^browser/automation/'],
           ],
         }],
+        ['enable_session_service!=1', {
+          'sources!': [
+            'browser/sessions/session_restore.cc',

[sky, 2012/04/04 21:04:51]

Don't you want to remove the .h's too?

[Yaron, 2012/04/04 21:36:18]

I suppose I could but I thought that it doesn't matter. In other words, the .h
will be included regardless of what gyp says and I thought gyp would only govern
what .o files are included. It doesn't hurt though, so I added it. Or maybe it
also matters for non-make/ninja builds?

+            'browser/sessions/session_service.cc',
+            'browser/sessions/session_service_factory.cc',
+          ],
+        }],
         ['OS=="android"', {
           'sources': [
             'browser/sync/glue/synced_window_delegate_registry.cc',
@@ -4517,9 +4524,6 @@
             'browser/ui/browser_tab_restore_service_delegate.cc',
             'browser/ui/sync/browser_synced_window_delegate.cc',
 
-            # Custom implementation of session_restore for Android.
-            'browser/sessions/session_restore.cc',
-
             'browser/ui/sad_tab_helper.cc',
             'browser/ui/webui/certificate_viewer_webui.cc',
             'browser/ui/window_sizer.cc',