ohos: Add basic IME and keyboard support (#34188)

* ohos: Add basic IME and keyboard support

- Add extremely basic support for keyboard events
- Add basic IME support
   - Showing and hiding the IME
   - inserting text
   - deleting characters
   - very basic configuration of the IME

Signed-off-by: Jonathan Schwender <jonathan.schwender@huawei.com>

* Apply suggestions from code review

Improve the log message

Co-authored-by: Josh Matthews <josh@joshmatthews.net>
Signed-off-by: Jonathan Schwender <55576758+jschwe@users.noreply.github.com>

* Update ports/servoshell/egl/ohos.rs

Co-authored-by: Mukilan Thiyagarajan <mukilanthiagarajan@gmail.com>
Signed-off-by: Jonathan Schwender <55576758+jschwe@users.noreply.github.com>

* ohos: Bump the minimum required SDK version to 5.0

Signed-off-by: Jonathan Schwender <jonathan.schwender@huawei.com>

* ohos: Remove pub from callbacks

The callbacks don't need to be public, as we will be registering them.

Signed-off-by: Jonathan Schwender <jonathan.schwender@huawei.com>

* Rename composition event

Signed-off-by: Jonathan Schwender <jonathan.schwender@huawei.com>

* ohos: clippy in log

Signed-off-by: Jonathan Schwender <jonathan.schwender@huawei.com>

* ohos: address some clippy warnings

Signed-off-by: Jonathan Schwender <jonathan.schwender@huawei.com>

* ohos: Raise Error in mach if unsupported SDK version is used.

Signed-off-by: Jonathan Schwender <jonathan.schwender@huawei.com>

* Add keyboard-types dependency for android

Signed-off-by: Jonathan Schwender <jonathan.schwender@huawei.com>

---------

Signed-off-by: Jonathan Schwender <jonathan.schwender@huawei.com>
Signed-off-by: Jonathan Schwender <55576758+jschwe@users.noreply.github.com>
Co-authored-by: Josh Matthews <josh@joshmatthews.net>
Co-authored-by: Mukilan Thiyagarajan <mukilanthiagarajan@gmail.com>

components/shared/compositing/constellation_msg.rs

@@ -10,7 +10,7 @@ use base::id::{BrowsingContextId, PipelineId, TopLevelBrowsingContextId, WebView
 use base::Epoch;
 use embedder_traits::Cursor;
 use ipc_channel::ipc::IpcSender;
-use keyboard_types::KeyboardEvent;
+use keyboard_types::{CompositionEvent, KeyboardEvent};
 use script_traits::{
     AnimationTickType, CompositorEvent, GamepadEvent, LogEntry, MediaSessionActionType,
     TraversalDirection, WebDriverCommandMsg, WindowSizeData, WindowSizeType,
@@ -34,6 +34,8 @@ pub enum ConstellationMsg {
     IsReadyToSaveImage(HashMap<PipelineId, Epoch>),
     /// Inform the constellation of a key event.
     Keyboard(KeyboardEvent),
+    /// Inform the constellation of a composition event (IME).
+    IMECompositionEvent(CompositionEvent),
     /// Whether to allow script to navigate.
     AllowNavigationResponse(PipelineId, bool),
     /// Request to load a page.
@@ -103,6 +105,7 @@ impl ConstellationMsg {
             GetFocusTopLevelBrowsingContext(..) => "GetFocusTopLevelBrowsingContext",
             IsReadyToSaveImage(..) => "IsReadyToSaveImage",
             Keyboard(..) => "Keyboard",
+            IMECompositionEvent(..) => "IMECompositionEvent",
             AllowNavigationResponse(..) => "AllowNavigationResponse",
             LoadUrl(..) => "LoadUrl",
             TraverseHistory(..) => "TraverseHistory",