Add window manager component.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 6048a198b3d2e9df61d3b6449f9569676c8b6516..a46a119d1068cceaa20cf26f98b4194e2895b187 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -26,11 +26,15 @@
 
             # Whether or not we are building the Ash shell.
             'use_ash%': 0,
+
+            # Whether or not we are building the window manager.
+            'use_wm%': 0,
           },
           # Copy conditionally-set variables out one scope.
           'chromeos%': '<(chromeos)',
           'use_aura%': '<(use_aura)',
           'use_ash%': '<(use_ash)',
+          'use_wm%': '<(use_wm)',
 
           # Whether we are using Views Toolkit
           'toolkit_views%': 0,
@@ -64,6 +68,12 @@
               'use_aura%': 1,
             }],
 
+            # Wm implies ash.
+            ['use_wm==1', {
+              'use_ash%': 1,
+              'use_aura%': 1,
+            }],
+
             # For now, Windows builds that |use_aura| should also imply using
             # ash. This rule should be removed for the future when Windows is
             # using the aura windows without the ash interface.
@@ -91,6 +101,7 @@
         'chromeos%': '<(chromeos)',
         'use_aura%': '<(use_aura)',
         'use_ash%': '<(use_ash)',
+        'use_wm%': '<(use_wm)',
         'use_openssl%': '<(use_openssl)',
         'enable_viewport%': '<(enable_viewport)',
         'enable_hidpi%': '<(enable_hidpi)',
@@ -165,6 +176,7 @@
       'toolkit_uses_gtk%': '<(toolkit_uses_gtk)',
       'use_aura%': '<(use_aura)',
       'use_ash%': '<(use_ash)',
+      'use_wm%': '<(use_wm)',
       'use_openssl%': '<(use_openssl)',
       'enable_viewport%': '<(enable_viewport)',
       'enable_hidpi%': '<(enable_hidpi)',
@@ -675,6 +687,7 @@
     'ui_compositor_image_transport%': '<(ui_compositor_image_transport)',
     'use_aura%': '<(use_aura)',
     'use_ash%': '<(use_ash)',
+    'use_wm%': '<(use_wm)',
     'use_openssl%': '<(use_openssl)',
     'use_nss%': '<(use_nss)',
     'os_bsd%': '<(os_bsd)',
@@ -1389,6 +1402,9 @@
       ['use_ash==1', {
         'grit_defines': ['-D', 'use_ash'],
       }],
+      ['use_wm==1', {
+        'grit_defines': ['-D', 'use_wm'],
+      }],
       ['use_nss==1', {
         'grit_defines': ['-D', 'use_nss'],
       }],
@@ -1716,6 +1732,9 @@
       ['use_ash==1', {
         'defines': ['USE_ASH=1'],
       }],
+      ['use_wm==1', {
+        'defines': ['USE_WM=1'],
+      }],
       ['use_default_render_theme==1', {
         'defines': ['USE_DEFAULT_RENDER_THEME=1'],
       }],