Remove the GetCaption dataprovider method

BUILD.gn

 # Copyright 2016 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_overrides/v8.gni")
 import("//testing/test.gni")
 import("pdfium.gni")
 
 config("pdfium_common_config") {
   cflags = []
@@ skipping 1294 matching lines @@
       "xfa/fwl/core/ifwl_pushbutton.h",
       "xfa/fwl/core/ifwl_scrollbar.cpp",
       "xfa/fwl/core/ifwl_scrollbar.h",
       "xfa/fwl/core/ifwl_spinbutton.cpp",
       "xfa/fwl/core/ifwl_spinbutton.h",
       "xfa/fwl/core/ifwl_themeprovider.h",
       "xfa/fwl/core/ifwl_timer.cpp",
       "xfa/fwl/core/ifwl_timer.h",
       "xfa/fwl/core/ifwl_timerinfo.cpp",
       "xfa/fwl/core/ifwl_timerinfo.h",
-      "xfa/fwl/core/ifwl_tooltip.cpp",
-      "xfa/fwl/core/ifwl_tooltip.h",
       "xfa/fwl/core/ifwl_widget.cpp",
       "xfa/fwl/core/ifwl_widget.h",
       "xfa/fwl/core/ifwl_widgetdelegate.h",
       "xfa/fwl/core/ifwl_widgetmgrdelegate.h",
       "xfa/fwl/theme/cfwl_arrowdata.cpp",
       "xfa/fwl/theme/cfwl_arrowdata.h",
       "xfa/fwl/theme/cfwl_barcodetp.cpp",
       "xfa/fwl/theme/cfwl_barcodetp.h",
       "xfa/fwl/theme/cfwl_carettp.cpp",
       "xfa/fwl/theme/cfwl_carettp.h",
@@ skipping 515 matching lines @@
       "//samples",
     ]
   }
   group("fuzzers") {
     testonly = true
     deps = [
       "//testing/libfuzzer",
     ]
   }
 }