Add a mojo channel for frame messages.

content/common/input/input_handler.mojom

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+module content.mojom;
+
+import "services/ui/public/interfaces/ime/ime.mojom";
+import "ui/gfx/geometry/mojo/geometry.mojom";
+
+interface FrameInputHandler
+{
+  SetCompositionFromExistingText(int32 start, int32 end, array<ui.mojom.CompositionUnderline> underlines);
+  ExtendSelectionAndDelete(int32 before, int32 after);
+  DeleteSurroundingText(int32 before, int32 after);
+  DeleteSurroundingTextInCodePoints(int32 before, int32 after);
+  SetEditableSelectionOffsets(int32 start, int32 end);
+  ExecuteEditCommand(string command, string? value);
+  Undo();
+  Redo();
+  Cut();
+  Copy();
+  CopyToFindPboard();
+  Paste();
+  PasteAndMatchStyle();
+  Replace(string word);
+  ReplaceMisspelling(string word);
+  Delete();
+  SelectAll();
+  CollapseSelection();
+  SelectRange(gfx.mojom.Point base, gfx.mojom.Point extent);
+  AdjustSelectionByCharacterOffset(int32 start, int32 end);
+  MoveRangeSelectionExtent(gfx.mojom.Point extent);
+};