fix allocator shim for multiple_dll debug build

allocator.gyp removes libcmt/libcmtd from link via direct_dependent_settings
so having chrome_main_dll depend on it fixes the link.

(I think it probably doesn't work in non-multiple_dll Debug either, but
linking Debug-static_library with symbols doesn't work anyway so likely no
one noticed.)

R=jamesr@chromium.org
BUG=262396

Review URL: https://chromiumcodereview.appspot.com/22329002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@215818 0039d316-1c4b-4281-b951-d872f2087c98

chrome/chrome_dll.gypi

@@ -227,6 +227,13 @@
                   ],
                 },
               },
+              'conditions': [
+                ['win_use_allocator_shim==1', {
+                  'dependencies': [
+                    '<(allocator_target)',
+                  ],
+                }],
+              ]
             }],
             ['chrome_multiple_dll==1', {
               'defines': [