storage: Isolate sessionStorage per top-level browsing context and copy sessionStorage when creating a new auxiliary browsing context (#37803)

This pull request introduces changes to the storage subsystem to:
- Isolate sessionStorage per top-level browsing context (WebViewId), in
  addition to origin.
- Copy sessionStorage when creating a new auxiliary browsing context
without
  noopener, as required by the corresponding spec
 
These changes bring Servo closer to spec compliance, matching expected
browser
behavior.

Testing: This work affects observable behavior. As a result, some
previously
failing WPT tests now pass. No new tests are added, since the behavior
is
already covered by existing web-platform-tests.

Fixes: #21291

---------

Signed-off-by: Jan Varga <jan.varga@gmail.com>

components/shared/net/storage_thread.rs

@@ -2,6 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+use base::id::WebViewId;
 use ipc_channel::ipc::IpcSender;
 use malloc_size_of_derive::MallocSizeOf;
 use profile_traits::mem::ReportsChan;
@@ -18,31 +19,58 @@ pub enum StorageType {
 #[derive(Debug, Deserialize, Serialize)]
 pub enum StorageThreadMsg {
     /// gets the number of key/value pairs present in the associated storage data
-    Length(IpcSender<usize>, ServoUrl, StorageType),
+    Length(IpcSender<usize>, StorageType, WebViewId, ServoUrl),
 
     /// gets the name of the key at the specified index in the associated storage data
-    Key(IpcSender<Option<String>>, ServoUrl, StorageType, u32),
+    Key(
+        IpcSender<Option<String>>,
+        StorageType,
+        WebViewId,
+        ServoUrl,
+        u32,
+    ),
 
     /// Gets the available keys in the associated storage data
-    Keys(IpcSender<Vec<String>>, ServoUrl, StorageType),
+    Keys(IpcSender<Vec<String>>, StorageType, WebViewId, ServoUrl),
 
     /// gets the value associated with the given key in the associated storage data
-    GetItem(IpcSender<Option<String>>, ServoUrl, StorageType, String),
+    GetItem(
+        IpcSender<Option<String>>,
+        StorageType,
+        WebViewId,
+        ServoUrl,
+        String,
+    ),
 
     /// sets the value of the given key in the associated storage data
     SetItem(
         IpcSender<Result<(bool, Option<String>), ()>>,
-        ServoUrl,
         StorageType,
+        WebViewId,
+        ServoUrl,
         String,
         String,
     ),
 
     /// removes the key/value pair for the given key in the associated storage data
-    RemoveItem(IpcSender<Option<String>>, ServoUrl, StorageType, String),
+    RemoveItem(
+        IpcSender<Option<String>>,
+        StorageType,
+        WebViewId,
+        ServoUrl,
+        String,
+    ),
 
     /// clears the associated storage data by removing all the key/value pairs
-    Clear(IpcSender<bool>, ServoUrl, StorageType),
+    Clear(IpcSender<bool>, StorageType, WebViewId, ServoUrl),
+
+    /// clones all storage data of the given top-level browsing context for a new browsing context.
+    /// should only be used for sessionStorage.
+    Clone {
+        sender: IpcSender<()>,
+        src: WebViewId,
+        dest: WebViewId,
+    },
 
     /// send a reply when done cleaning up thread resources and then shut it down
     Exit(IpcSender<()>),