Updates postMessage() to clone FileSystemFileHandle and
FileSystemDirectoryHandle objects for same origin targets.  Including
a FileSystemHandle object with a cross origin message fails by
dispatching a 'messageerror' event instead of 'message' event.

The change consists of four parts:

(1) Updates V8ScriptValueSerializerForModules to serialize
FileSystemFileHandle and FileSystemDirectoryHandle into
blink::SerializedScriptValue, by following these steps:

 * Write a tag for the handle type (file or directory).

 * Write the name of the file or directory.

 * Creates a mojom::blink::NativeFileSystemTransferTokenPtr  by calling
   blink:NativeFileSystemHandle::Transfer().  This token informs the
   storage::NativeFileSystemManagerImpl that a transfer is in progress.
   The NativeFileSystemManagerImpl creates a
   NativeFileSystemTransferTokenImpl to store the information required
   to clone the handle.

 * Stores the token in
   blink::SerializedScriptValue::native_file_system_tokens_.  This
   array tracks all cloned FileSystemFileHandle. The
   blink::mojom::CloneableMessage struct is also updated to hold this
   array for MessagePort and BroadcastChannels.

 * Write the index of the token in the native_file_system_tokens_
   array.

(2) Updates V8ScriptValueDeserializerForModules to deserialize
FileSystemFileHandle objects when creating clones for the message
targets.  This is the inverse of (1).  Deserializing uses
mojom::blink::NativeFileSystemManager to redeem the token, which
creates the mojom::blink::NativeFileSystemFileHandlePtr or
mojom::blink::NativeFileSystemDirectoryHandlePtr using the info
stored by NativeFileSystemTransferTokenImpl.

(3) Updates content::NativeFileSystemManagerImpl to support token
transfers.  To redeem a token, NativeFileSystemManagerImpl receives
a mojo message that includes the token as well as a request for a
handle interface like mojom::blink::NativeFileSystemFileHandlePtr.
NativeFileSystemManagerImpl finds the token and then binds the request.
Token redemption does not return any results.  Token redemption should
never fail, unless a render process is misbehaving.
NativeFileSystemManagerImpl performs a few sanity checks before binding
the mojo request, including a token existence check, a handle type
check and an origin check.  If any of the sanity checks fail,
NativeFileSystemManagerImpl silently fails closing the redeemed
FileHandle's pipe.

(4) Adds a cross origin check to window and message port messaging.
Most message targets, like dedicated workers, are same origin only.
However, both windows and message port messages can go cross origin.
When a cross origin message includes a FileSystemHandle, the message
must fail with a 'messageerror' event to prevent cross origin access
to the FileSystemHandle.

Messaging between windows already included origin information before
this change. This change adds a NativeFileSystem origin check before
dispatching a message event to a window.  The message event is
replaced with  a message error when a cross origin NativeFileSystem
object exists in the message data.

For message ports, no sender origin information existed before this
change.  This change updates the CloneableMessage structs to
include a 'sender_origin' url::Origin property.  Message ports use
this property to perform the same cross origin NativeFileSystem
check as the window.

The NativeFileSystemManagerImpl performs an additional origin check
before binding the FileSystemHandle mojo request.  The
NativeFileSystemManagerImpl cannot trust the postMessage() origin
check performed in the render process.

Bug: 955192
Change-Id: Ieeb76bd8102067d70c5d7719622ecd4930c3a88f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1791942
Commit-Queue: Steve Becker <stevebe@microsoft.com>
Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Marijn Kruisselbrink <mek@chromium.org>
Reviewed-by: Olivier Yiptong <oyiptong@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709407}