Use explicit WebString <-> string16 conversion methods in storage API files

third_party/WebKit/Source/platform/exported/FilePathConversion.cpp

Index: third_party/WebKit/Source/platform/exported/FilePathConversion.cpp
diff --git a/third_party/WebKit/Source/platform/exported/FilePathConversion.cpp b/third_party/WebKit/Source/platform/exported/FilePathConversion.cpp
index bd394f38940b8b0dcbbc75bb4983eb4404180b6d..cf4efaeac0ce76de591730ad64b5527998ce6c8f 100644
--- a/third_party/WebKit/Source/platform/exported/FilePathConversion.cpp
+++ b/third_party/WebKit/Source/platform/exported/FilePathConversion.cpp
@@ -31,4 +31,15 @@ base::FilePath WebStringToFilePath(const WebString& webString) {
 #endif
 }
 
+WebString FilePathToWebString(const base::FilePath& path) {
+  if (path.empty())
+    return WebString();
+
+#if OS(POSIX)
+  return WebString::fromUTF8(path.value());
+#else
+  return WebString::fromUTF16(path.AsUTF16Unsafe());
+#endif
+}
+
 }  // namespace blink