net: Update FileStream to use base::File instead of PlatformFile.

base/file_util_unittest.cc

Index: base/file_util_unittest.cc
diff --git a/base/file_util_unittest.cc b/base/file_util_unittest.cc
index 8ee55ff4a7aed70857e44b3ce86a6fb610d962cf..b37865755f31eecadce58abcd41ca274ede1fbfe 100644
--- a/base/file_util_unittest.cc
+++ b/base/file_util_unittest.cc
@@ -2449,9 +2449,9 @@ TEST_F(FileUtilTest, ValidContentUriTest) {
 
   // We should be able to read the file.
   char* buffer = new char[image_size];
-  int fd = OpenContentUriForRead(path);
-  EXPECT_LT(0, fd);
-  EXPECT_TRUE(ReadFromFD(fd, buffer, image_size));
+  File file = OpenContentUriForRead(path);
+  EXPECT_TRUE(file.IsValid());
+  EXPECT_TRUE(file.ReadAtCurrentPos(buffer, image_size));
   delete[] buffer;
 }
 
@@ -2464,8 +2464,8 @@ TEST_F(FileUtilTest, NonExistentContentUriTest) {
   EXPECT_FALSE(GetFileSize(path, &size));
 
   // We should not be able to read the file.
-  int fd = OpenContentUriForRead(path);
-  EXPECT_EQ(-1, fd);
+  File file = OpenContentUriForRead(path);
+  EXPECT_FALSE(file.IsValid());
 }
 #endif