Add missing dependencies.

chrome/chrome_tests_unit.gypi

 # Copyright 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 {
   'variables': {
     'chrome_unit_tests_sources': [
       # histograms.xml is analyzed by AboutFlagsHistogramTest, so this
       # dependency is needed to make commit bots run unit_tests on
       # histograms.xml changes.
       '../tools/metrics/histograms/histograms.xml',
@@ skipping 2187 matching lines @@
         '../skia/skia.gyp:skia',
         '../third_party/cacheinvalidation/cacheinvalidation.gyp:cacheinvalidation',
         '../third_party/icu/icu.gyp:icui18n',
         '../third_party/icu/icu.gyp:icuuc',
         '../third_party/libxml/libxml.gyp:libxml',
         '../ui/base/ui_base.gyp:ui_base_test_support',
         '../ui/gfx/gfx.gyp:gfx_test_support',
         '../ui/resources/ui_resources.gyp:ui_resources',
         'chrome_resources.gyp:chrome_resources',
         'chrome_resources.gyp:chrome_strings',
+        # Only needed at runtime.
+        '../third_party/mesa/mesa.gyp:osmesa',
       ],
       'include_dirs': [
         '..',
       ],
       'msvs_settings': {
         'VCLinkerTool': {
           'conditions': [
             ['incremental_chrome_dll==1', {
               'UseLibraryDependencyInputs': "true",
             }],
@@ skipping 684 matching lines @@
               'dependencies': [
                 '../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
               ],
             }],
           ],
         },
       ],
     }],
   ],  # 'conditions'
 }