Mark several messages as [UnlimitedSize]

These messages were identified as occasionally exceeding the soft
message size limit. No functional changes here, only suppressions and
TODOs.

Bug: 1141980,1141985,1141987,1141990,1142000,1142008,1142011,1142013
Change-Id: Icd1a060b9bd082bfa204f44a3a12a43c8812c0fb
Fixed: 1142019
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2495789
Commit-Queue: Ken Rockot <rockot@google.com>
Auto-Submit: Ken Rockot <rockot@google.com>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821018}

chrome/common/media/webrtc_logging.mojom

@@ -15,6 +15,11 @@ struct WebRtcLoggingMessage {
 // Used to listen for new log messages and events from the agent.
 interface WebRtcLoggingClient {
   // New log messages are sent in batches to limit the frequency of calls.
+  //
+  // TODO(crbug.com/1142013): Investigate whether the [UnlimitedSize] tag can
+  // be removed here by either chunking the messages into multiple calls or
+  // using something like BigString for WebRtcLoggingMessage's data.
+  [UnlimitedSize]
   OnAddMessages(array<WebRtcLoggingMessage> messages);
 
   // Called in response to |Stop| being called on the agent. Any pending

components/arc/mojom/file_system.mojom

@@ -425,6 +425,11 @@ interface FileSystemInstance {
   // Requests MediaProvider to scan specified files.
   // When the specified file does not exist, the corresponding entry in
   // MediaProvider is removed.
+  //
+  // NOTE: We use [UnlimitedSize] here because `paths` may be arbitrarily large
+  // and there have been crash dumps indicating that it actually happens with
+  // this message. See https://crbug.com/1142019.
+  [UnlimitedSize]
   RequestMediaScan@0(array<string> paths);
 
   // Reloads and refreshes entries in MediaStore under |directory_path|.

components/services/print_compositor/public/mojom/print_compositor.mojom

@@ -48,7 +48,11 @@ interface PrintCompositor {
 
   // Sets the accessibility tree for the overall document. This is needed
   // to generate tagged (accessible) PDFs.
-  [EnableIf=enable_tagged_pdf]
+  //
+  // TODO(crbug.com/1141990): AXTreeUpdate can be quite large, hence the
+  // [UnlimitedSize] tag. It may be possible to remove this if AXTreeUpdate
+  // can be reworked to avoid very large serialized values.
+  [EnableIf=enable_tagged_pdf, UnlimitedSize]
   SetAccessibilityTree(ax.mojom.AXTreeUpdate accessibility_tree);
 
   // Requests to composite a page and convert it into a PDF file.

content/common/frame.mojom

@@ -106,6 +106,10 @@ interface Frame {
   // Requests a one-time snapshot of the accessibility tree without enabling
   // accessibility if it wasn't already enabled.
   // See ui/accessibility/ax_mode.h for valid values of |ax_mode|.
+  //
+  // TODO(crbug.com/1141990): AXTreeUpdate can be quite large, hence the
+  // [UnlimitedSize] tag. It may be possible to remove this if AXTreeUpdate
+  // can be reworked to avoid very large serialized values.
   SnapshotAccessibilityTree(uint32 ax_mode)
       => (ax.mojom.AXTreeUpdate snapshot);
 
@@ -529,6 +533,10 @@ interface FrameHost {
       mojo_base.mojom.String16 source_id);
 
   // Notifies the browser that this frame has new session history information.
+  //
+  // NOTE: PageState can be quite large when serialized, and its message
+  // structure must remain stable; hence [UnlimitedSize] for this message.
+  [UnlimitedSize]
   UpdateState(PageState state);
 
   // Requests that the given URL be opened in the specified manner.

content/common/media/media_log_records.mojom

@@ -10,5 +10,9 @@ import "media/mojo/mojom/media_types.mojom";
 // media pipeline. It sends media event logs from renderer to browser.
 interface MediaInternalLogRecords {
   // Sends batched media logs to MediaInternalLogRecordsImpl::Log
+  //
+  // TODO(crbug.com/1141985): Investigate whether we can avoid degenerate cases
+  // leading to the very large messages which necessitate [UnlimitedSize].
+  [UnlimitedSize]
   Log(array<media.mojom.MediaLogRecord> events);
-};
\ No newline at end of file
+};

content/common/web_ui.mojom

@@ -10,6 +10,10 @@ import "mojo/public/mojom/base/values.mojom";
 interface WebUIHost {
   // A message from HTML-based UI. When (trusted) JavaScript calls
   // send(message, args), this message is sent to the browser.
+  //
+  // Because `args` may be an arbitrarily complex object, we tag this with
+  // [UnlimitedSize] to ignore soft message length limits within Mojo.
+  [UnlimitedSize]
   Send(string message, mojo_base.mojom.ListValue args);
 };
 

services/viz/public/mojom/compositing/compositor_frame_sink.mojom

@@ -53,6 +53,11 @@ interface CompositorFrameSink {
   // For successful swaps, the implementation must call
   // DidReceiveCompositorFrameAck() asynchronously when the frame has been
   // processed in order to unthrottle the next frame.
+  //
+  // TODO(crbug.com/1141980): Investigate whether it's possible to alter the
+  // CompositorFrame structure to be less likely to exceed soft message size
+  // limits and remove [UnlimitedSize] here.
+  [UnlimitedSize]
   SubmitCompositorFrame(LocalSurfaceId local_surface_id,
                         CompositorFrame frame,
                         HitTestRegionList? hit_test_region_list,

third_party/blink/public/mojom/choosers/file_chooser.mojom

@@ -104,6 +104,10 @@ struct FileChooserResult {
 interface FileChooser {
   // Ask a user to choose files interactively.  Null |result| is returned if the
   // user canceled a dialog, or the request is not accepted.
+  //
+  // TODO(crbug.com/1142011): Consider chunking the reply into multiple messages
+  // on a separate interface to avoid one very large IPC in some corner cases.
+  [UnlimitedSize]
   OpenFileChooser(FileChooserParams params) => (FileChooserResult? result);
 
   // Ask to enumerate files which are descendants of the specified directory.

third_party/blink/public/mojom/devtools/devtools_agent.mojom

@@ -142,11 +142,16 @@ interface DevToolsSessionHost {
   // |updates| are the session state deltas for future reattach (see
   // DevToolsAgent), may be missing if the state did not change since
   // last time.
+  //
+  // TODO(crbug.com/1142000): Investigate whether it's possible to remove
+  // [UnlimitedSize] from these messages.
+  [UnlimitedSize]
   DispatchProtocolResponse(DevToolsMessage message,
                            int32 call_id,
                            DevToolsSessionState? updates);
 
   // Dispatches protocol notification to a remote debugging client.
+  [UnlimitedSize]
   DispatchProtocolNotification(DevToolsMessage message,
                                DevToolsSessionState? updates);
 };