cros-suggest: add required suggestion proto ops

This CL adds the required proto operations to request and return
suggestion candidates to the IME shared library.

Bug: 1146266
Change-Id: Ie3636e7ef9abf546c2e0ec5c11a8b47cd865f8b8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2583669
Commit-Queue: Curtis McMullan <curtismcmullan@chromium.org>
Reviewed-by: Darren Shen <shend@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#837862}

chromeos/services/ime/public/mojom/input_engine.mojom

@@ -143,6 +143,50 @@ struct AutocorrectSpan {
   string original_text;
 };
 
+// Proposed candidate for completing some text.
+// TODO(crbug/1159614): Remove in favour of sending serialized proto data.
+struct CompletionCandidate {
+  // The candidate text
+  string text;
+
+  // Normalized confidence scoring for the candidate
+  float normalized_score;
+};
+
+// Single request to generate suggestion candidates from the given context.
+// TODO(crbug/1159614): Remove in favour of sending serialized proto data.
+struct SuggestionsRequest {
+  // The preceding text used to produced the suggestions.
+  string text;
+
+  // Optional: any candidates generated to complete the current text.
+  array<CompletionCandidate> completion_candidates;
+};
+
+// A suggestion candidate containing multiple predicted words.
+// TODO(crbug/1159614): Remove in favour of sending serialized proto data.
+struct MultiWordSuggestionCandidate {
+  // The words predicted.
+  string text;
+
+  // The normalized confidence scoring for the prediction.
+  float normalized_score;
+};
+
+// Represents a single generated suggestion candidate.
+// TODO(crbug/1159614): Remove in favour of sending serialized proto data.
+union SuggestionCandidate {
+  // A suggestion candidate that contains multiple words.
+  MultiWordSuggestionCandidate multi_word;
+};
+
+// Encapsulates the results of a suggestions request.
+// TODO(crbug/1159614): Remove in favour of sending serialized proto data.
+struct SuggestionsResponse {
+  // A list of suggestion candidates generated.
+  array<SuggestionCandidate> candidates;
+};
+
 // Manages access to a set of IME engines, implemented by the IME service
 // itself. The IME framework in the browser process is responsible for brokering
 // the connection between the IME service and the IME extension, but does not

chromeos/services/ime/public/proto/messages.proto

@@ -40,6 +40,8 @@ message PublicMessage {
     FinishComposition finish_composition = 12;
     DeleteSurroundingText delete_surrounding_text = 13;
     HandleAutocorrect handle_autocorrect = 14;
+    SuggestionsRequest suggestions_request = 15;
+    SuggestionsResponse suggestions_response = 16;
   }
 }
 
@@ -197,3 +199,36 @@ message DeleteSurroundingText {
 message HandleAutocorrect {
   optional AutocorrectSpan autocorrect_span = 1;
 }
+
+// Protobuf version of CompletionCandidate in
+// chromeos/services/ime/public/mojom/input_engine.mojom
+message CompletionCandidate {
+  optional string text = 1;
+  optional float normalized_score = 2;
+}
+
+// Protobuf version of SuggestionsRequest in
+// chromeos/services/ime/public/mojom/input_engine.mojom
+message SuggestionsRequest {
+  optional string text = 1;
+  repeated CompletionCandidate completion_candidates = 2;
+}
+
+// Protobuf version of MultiWordSuggestionCandidate in
+// chromeos/services/ime/public/mojom/input_engine.mojom
+message MultiWordSuggestionCandidate {
+  optional string text = 1;
+  optional float normalized_score = 2;
+}
+
+// Protobuf version of SuggestionCandidate in
+// chromeos/services/ime/public/mojom/input_engine.mojom
+message SuggestionCandidate {
+  oneof candidate { MultiWordSuggestionCandidate multi_word = 1; }
+}
+
+// Protobuf version of SuggestionsResponse in
+// chromeos/services/ime/public/mojom/input_engine.mojom
+message SuggestionsResponse {
+  repeated SuggestionCandidate candidates = 1;
+}