Rename "CheckWritable" to "PrepareForWritableApp" to reflect the actual behavior.

chrome/browser/chromeos/file_manager/filesystem_api_util.h

Index: chrome/browser/chromeos/file_manager/filesystem_api_util.h
diff --git a/chrome/browser/chromeos/file_manager/filesystem_api_util.h b/chrome/browser/chromeos/file_manager/filesystem_api_util.h
index 3ce7a6be15c05f482090b3af7a99f835762bbbf6..a0afb9f664d2f92c7330fd044492bd90778d30f6 100644
--- a/chrome/browser/chromeos/file_manager/filesystem_api_util.h
+++ b/chrome/browser/chromeos/file_manager/filesystem_api_util.h
@@ -40,9 +40,10 @@ void IsNonNativeLocalPathDirectory(
     const base::FilePath& path,
     const base::Callback<void(bool)>& callback);
 
-// Prepares a writable file at |path|, i.e., creates a file there if it didn't
-// exist, and asynchronously sends to |callback| whether it succeeded.
-void PrepareNonNativeLocalPathWritableFile(
+// Ensures a file exists at |path|, i.e., it does nothing if a file is already
+// present, or creates a file there if it isn't, and asynchronously sends to
+// |callback| whether it succeeded.
+void PrepareNonNativeLocalFileForWritableApp(
     Profile* profile,
     const base::FilePath& path,
     const base::Callback<void(bool)>& callback);