[Extensions] Don't allow gin::Define to be overridden

extensions/renderer/file_system_natives.cc

 // 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.
 
 #include "extensions/renderer/file_system_natives.h"
 
 #include <string>
 
 #include "extensions/common/constants.h"
 #include "extensions/renderer/script_context.h"
@@ skipping 13 matching lines @@
   RouteFunction("GetIsolatedFileSystem",
                 base::Bind(&FileSystemNatives::GetIsolatedFileSystem,
                            base::Unretained(this)));
   RouteFunction("CrackIsolatedFileSystemName",
                 base::Bind(&FileSystemNatives::CrackIsolatedFileSystemName,
                            base::Unretained(this)));
 }
 
 void FileSystemNatives::GetIsolatedFileSystem(
     const v8::FunctionCallbackInfo<v8::Value>& args) {
-  DCHECK(args.Length() == 1 || args.Length() == 2);
-  DCHECK(args[0]->IsString());
+  CHECK(args.Length() == 1 || args.Length() == 2);
+  CHECK(args[0]->IsString());
   std::string file_system_id(*v8::String::Utf8Value(args[0]));
   blink::WebLocalFrame* webframe =
       blink::WebLocalFrame::frameForContext(context()->v8_context());
   DCHECK(webframe);
 
   GURL context_url =
       extensions::ScriptContext::GetDataSourceURLForFrame(webframe);
   CHECK(context_url.SchemeIs(extensions::kExtensionScheme));
 
   std::string name(storage::GetIsolatedFileSystemName(context_url.GetOrigin(),
                                                       file_system_id));
 
   // The optional second argument is the subfolder within the isolated file
   // system at which to root the DOMFileSystem we're returning to the caller.
   std::string optional_root_name;
   if (args.Length() == 2) {
-    DCHECK(args[1]->IsString());
+    CHECK(args[1]->IsString());
     optional_root_name = *v8::String::Utf8Value(args[1]);
   }
 
   GURL root_url(storage::GetIsolatedFileSystemRootURIString(
       context_url.GetOrigin(), file_system_id, optional_root_name));
 
   args.GetReturnValue().Set(
       blink::WebDOMFileSystem::create(webframe,
                                       blink::WebFileSystemTypeIsolated,
                                       blink::WebString::fromUTF8(name),
                                       root_url)
           .toV8Value(context()->v8_context()->Global(), args.GetIsolate()));
 }
 
 void FileSystemNatives::GetFileEntry(
     const v8::FunctionCallbackInfo<v8::Value>& args) {
-  DCHECK(args.Length() == 5);
-  DCHECK(args[0]->IsString());
+  CHECK_EQ(5, args.Length());
+  CHECK(args[0]->IsString());
   std::string type_string = *v8::String::Utf8Value(args[0]);
   blink::WebFileSystemType type;
   bool is_valid_type = storage::GetFileSystemPublicType(type_string, &type);
   DCHECK(is_valid_type);
   if (is_valid_type == false) {
     return;
   }
 
-  DCHECK(args[1]->IsString());
-  DCHECK(args[2]->IsString());
-  DCHECK(args[3]->IsString());
+  CHECK(args[1]->IsString());
+  CHECK(args[2]->IsString());
+  CHECK(args[3]->IsString());
   std::string file_system_name(*v8::String::Utf8Value(args[1]));
   GURL file_system_root_url(*v8::String::Utf8Value(args[2]));
   std::string file_path_string(*v8::String::Utf8Value(args[3]));
   base::FilePath file_path = base::FilePath::FromUTF8Unsafe(file_path_string);
   DCHECK(storage::VirtualPath::IsAbsolute(file_path.value()));
 
-  DCHECK(args[4]->IsBoolean());
+  CHECK(args[4]->IsBoolean());
   blink::WebDOMFileSystem::EntryType entry_type =
       args[4]->BooleanValue() ? blink::WebDOMFileSystem::EntryTypeDirectory
                               : blink::WebDOMFileSystem::EntryTypeFile;
 
   blink::WebLocalFrame* webframe =
       blink::WebLocalFrame::frameForContext(context()->v8_context());
   DCHECK(webframe);
   args.GetReturnValue().Set(
       blink::WebDOMFileSystem::create(
           webframe,
@@ skipping 15 matching lines @@
   if (!storage::CrackIsolatedFileSystemName(filesystem_name, &filesystem_id))
     return;
 
   args.GetReturnValue().Set(v8::String::NewFromUtf8(args.GetIsolate(),
                                                     filesystem_id.c_str(),
                                                     v8::String::kNormalString,
                                                     filesystem_id.size()));
 }
 
 }  // namespace extensions