Add methods to add DataPack from open files

ui/base/resource/data_pack.cc

 // Copyright (c) 2012 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 "ui/base/resource/data_pack.h"
 
 #include <errno.h>
 
 #include "base/file_util.h"
 #include "base/logging.h"
@@ skipping 35 matching lines @@
 // We're crashing when trying to load a pak file on Windows.  Add some error
 // codes for logging.
 // http://crbug.com/58056
 enum LoadErrors {
   INIT_FAILED = 1,
   BAD_VERSION,
   INDEX_TRUNCATED,
   ENTRY_NOT_FOUND,
   HEADER_TRUNCATED,
   WRONG_ENCODING,
+  INIT_FAILED_FROM_FILE,
 
   LOAD_ERRORS_COUNT,
 };
 
 }  // namespace
 
 namespace ui {
 
 DataPack::DataPack(ui::ScaleFactor scale_factor)
     : resource_count_(0),
       text_encoding_type_(BINARY),
       scale_factor_(scale_factor) {
 }
 
 DataPack::~DataPack() {
 }
 
-bool DataPack::Load(const FilePath& path) {
+bool DataPack::LoadFromPath(const FilePath& path) {
   mmap_.reset(new file_util::MemoryMappedFile);
   if (!mmap_->Initialize(path)) {
     DLOG(ERROR) << "Failed to mmap datapack";
     UMA_HISTOGRAM_ENUMERATION("DataPack.Load", INIT_FAILED,
                               LOAD_ERRORS_COUNT);
     mmap_.reset();
     return false;
   }
+  return LoadImpl();
+}
 
+bool DataPack::LoadFromFile(base::PlatformFile file) {
+  mmap_.reset(new file_util::MemoryMappedFile);
+  if (!mmap_->Initialize(file)) {
+    DLOG(ERROR) << "Failed to mmap datapack";
+    UMA_HISTOGRAM_ENUMERATION("DataPack.Load", INIT_FAILED_FROM_FILE,
+                              LOAD_ERRORS_COUNT);
+    mmap_.reset();
+    return false;
+  }
+  return LoadImpl();
+}
+
+bool DataPack::LoadImpl() {
   // Sanity check the header of the file.
   if (kHeaderLength > mmap_->length()) {
     DLOG(ERROR) << "Data pack file corruption: incomplete file header.";
     UMA_HISTOGRAM_ENUMERATION("DataPack.Load", HEADER_TRUNCATED,
                               LOAD_ERRORS_COUNT);
     mmap_.reset();
     return false;
   }
 
   // Parse the header of the file.
@@ skipping 187 matching lines @@
       return false;
     }
   }
 
   file_util::CloseFile(file);
 
   return true;
 }
 
 }  // namespace ui