Remove Dart_GetScriptSource as it is not used anywhere.

runtime/vm/debugger_api_impl_test.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "include/dart_debugger_api.h"
 #include "platform/assert.h"
 #include "vm/dart_api_impl.h"
 #include "vm/thread.h"
 #include "vm/unit_test.h"
 
@@ skipping 1006 matching lines @@
     EXPECT(num_scripts >= 0);
     for (int i = 0; i < num_scripts; i++) {
       Dart_Handle script_url = Dart_ListGetAt(scripts, i);
       char const* chars;
       Dart_StringToCString(script_url, &chars);
       OS::Print("  script %d: '%s'\n", i + 1, chars);
     }
   }
 
   Dart_Handle lib_url = NewString(TestCase::url());
-  Dart_Handle source = Dart_GetScriptSource(lib_url, lib_url);
+  Dart_Handle source = Dart_ScriptGetSource((num_libs - 1), lib_url);
   EXPECT(Dart_IsString(source));
   char const* source_chars;
   Dart_StringToCString(source, &source_chars);
   OS::Print("\n=== source: ===\n%s", source_chars);
   EXPECT_STREQ(kScriptChars, source_chars);
 }
 
 
 TEST_CASE(GetLibraryURLs) {
   const char* kScriptChars =
@@ skipping 507 matching lines @@
 
   Dart_Handle retval = Invoke("main");
   EXPECT(Dart_IsError(retval));
   EXPECT(Dart_IsUnhandledExceptionError(retval));
   EXPECT_EQ(1, breakpoint_hit_counter);
 }
 
 #endif  // defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64).
 
 }  // namespace dart