Convert base::MemoryMappedFile to use File instead of PlatformFile.

media/filters/file_data_source.cc

Index: media/filters/file_data_source.cc
diff --git a/media/filters/file_data_source.cc b/media/filters/file_data_source.cc
index 341347e78a1be64c420ca73fcef77f2ed9103ceb..8fb310091754f73180bacd029ac9bab8a49ed9b0 100644
--- a/media/filters/file_data_source.cc
+++ b/media/filters/file_data_source.cc
@@ -15,21 +15,19 @@ FileDataSource::FileDataSource()
       force_streaming_(false) {
 }
 
-bool FileDataSource::Initialize(const base::FilePath& file_path) {
-  DCHECK(!file_.IsValid());
-
-  if (!file_.Initialize(file_path))
-    return false;
+FileDataSource::FileDataSource(base::File file)
+    : force_read_errors_(false),
+      force_streaming_(false) {
+  if (!file_.Initialize(file.Pass()))
+    return;
 
   UpdateHostBytes();
-  return true;
 }
 
-bool FileDataSource::InitializeFromPlatformFile(
-    const base::PlatformFile& file) {
+bool FileDataSource::Initialize(const base::FilePath& file_path) {
   DCHECK(!file_.IsValid());
 
-  if (!file_.Initialize(file))
+  if (!file_.Initialize(file_path))
     return false;
 
   UpdateHostBytes();