[Extensions Bindings] Add a bindings/ subdirectory under renderer

extensions/renderer/bindings/api_signature_unittest.cc

 // Copyright 2017 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.
 
-#include "extensions/renderer/api_signature.h"
+#include "extensions/renderer/bindings/api_signature.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/values.h"
-#include "extensions/renderer/api_binding_test.h"
-#include "extensions/renderer/api_binding_test_util.h"
-#include "extensions/renderer/api_invocation_errors.h"
-#include "extensions/renderer/api_type_reference_map.h"
-#include "extensions/renderer/argument_spec.h"
-#include "extensions/renderer/argument_spec_builder.h"
+#include "extensions/renderer/bindings/api_binding_test.h"
+#include "extensions/renderer/bindings/api_binding_test_util.h"
+#include "extensions/renderer/bindings/api_invocation_errors.h"
+#include "extensions/renderer/bindings/api_type_reference_map.h"
+#include "extensions/renderer/bindings/argument_spec.h"
+#include "extensions/renderer/bindings/argument_spec_builder.h"
 #include "gin/converter.h"
 
 namespace extensions {
 namespace {
 
 using SpecVector = std::vector<std::unique_ptr<ArgumentSpec>>;
 
 std::unique_ptr<APISignature> OneString() {
   SpecVector specs;
   specs.push_back(ArgumentSpecBuilder(ArgumentType::STRING, "string").Build());
@@ skipping 377 matching lines @@
     std::unique_ptr<base::ListValue> parsed;
     EXPECT_TRUE(signature->ConvertArgumentsIgnoringSchema(context, v8_args,
                                                           &parsed, &callback));
     ASSERT_TRUE(parsed);
     EXPECT_EQ(R"([{"not":"a string"}])", ValueToString(*parsed));
     EXPECT_TRUE(callback.IsEmpty());
   }
 }
 
 }  // namespace extensions