Avoid basename conflict in text_composition

ui/base/ime/BUILD.gn

 # Copyright 2015 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/ui.gni")
 import("//testing/test.gni")
 
 component("ime") {
   output_name = "ui_base_ime"
   sources = [
     "candidate_window.cc",
     "candidate_window.h",
     "chromeos/character_composer.cc",
     "chromeos/character_composer.h",
     "chromeos/component_extension_ime_manager.cc",
     "chromeos/component_extension_ime_manager.h",
-    "chromeos/composition_text.cc",
-    "chromeos/composition_text.h",
+    "chromeos/composition_text_chromeos.cc",
+    "chromeos/composition_text_chromeos.h",
     "chromeos/extension_ime_util.cc",
     "chromeos/extension_ime_util.h",
     "chromeos/fake_ime_keyboard.cc",
     "chromeos/fake_ime_keyboard.h",
     "chromeos/fake_input_method_delegate.cc",
     "chromeos/fake_input_method_delegate.h",
     "chromeos/ime_bridge.cc",
     "chromeos/ime_bridge.h",
     "chromeos/ime_keyboard.cc",
     "chromeos/ime_keyboard.h",
@@ skipping 130 matching lines @@
       "composition_text_util_pango.cc",
       "composition_text_util_pango.h",
     ]
   }
   if (use_x11) {
     configs += [ "//build/config/linux:x11" ]
     deps += [ "//ui/gfx/x" ]
   }
 
   if (is_win) {
-    cflags = [
-      "/wd4324",  # Structure was padded due to __declspec(align()), which is
-                  # uninteresting.
-    ]
+    cflags = [ "/wd4324" ]  # Structure was padded due to __declspec(align()), which is
+                            # uninteresting.
+
     libs = [ "imm32.lib" ]
   }
 
   if (use_ozone) {
     deps += [
       "//ui/ozone",
       "//ui/events/ozone:events_ozone_layout",
     ]
   }
 }