Remove a nonexistent file from BUILD.gn to fix Mac GN Build failure

ui/views/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 
 gypi_values = exec_script("//build/gypi_to_gn.py",
                           [ rebase_path("views.gyp") ],
@@ skipping 250 matching lines @@
       "//ui/events/platform/x11",
       "//ui/gfx/x",
     ]
   }
 
   if (is_mac) {
     # views_unittests not yet compiling on Mac. http://crbug.com/378134
     sources -= [
       "bubble/bubble_window_targeter_unittest.cc",
       "controls/native/native_view_host_unittest.cc",
-      "ime/input_method_bridge_unittest.cc",
       "widget/window_reorderer_unittest.cc",
     ]
   }
 }
 
 if (is_mac) {
   test("macviews_interactive_ui_tests") {
     sources = [
       "cocoa/bridged_native_widget_interactive_uitest.mm",
       "run_all_unittests.cc",
       "widget/native_widget_mac_interactive_uitest.mm",
     ]
     deps = [
       ":test_support",
       ":views",
       "//base",
       "//base/test:test_support",
       "//skia",
       "//testing/gtest",
       "//ui/base:test_support",
       "//ui/compositor",
       "//ui/resources",
       "//ui/resources:ui_test_pak",
       "//ui/strings",
     ]
   }
 }