Revise ui::DomKey to unify character and non-character codes.

ui/events/keycodes/dom/dom_key_data.inc

 // Copyright 2014 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.
 
 // This file has no header guard because it is explicily intended
 // to be included more than once with different definitions of the
 // macros DOM_KEY_MAP and DOM_KEY_MAP_DECLARATION.
 
 // This is a table of DOM Level 3 .key values, used to generate identifiers
 // (enums) and string tables. These names are defined by:
 //
 //   [0] DOM Level 3 KeyboardEvent key Values,
 //       http://www.w3.org/TR/DOM-Level-3-Events-key/
 //
 // That reference should be consulted on the meaning and usage of these
 // values; this file does not attempt to describe that.
 //
 // The names given in the table here directly match the DOM Level 3 value,
 // and for the most part the corresponding enum identifier is generated from
 // the name by converting W3C's CamelCaseStyle to Chromium's C_MACRO_STYLE.
 
 DOM_KEY_MAP_DECLARATION {
 

[kpschoedel, 2015/08/07 20:42:12]

In the previous code, there were some special cases and the function
|CharacterToDomKey()| to make sure that for the dual-coded values both the key
and character would match (e.g. key_=DomKey::BACK_SPACE character_='\b'). It was
possible to explictly construct a KeyEvent for which this was not true, which
would have behaved inconsistently.

The new representation ensures that KeyStringToDomKey("\b") ==
KeyStringToDomKey("Backspace") == DomKey::BACKSPACE == '\b' with no special
effort.

Since these values are in the name table, |DomKeyToKeyString()| returns the
standard names, and at the same time |DomKey::IsUnicode()| is true, which
matches the way the values are used. The cost is segregating them is this file,
so as not to interfere with the auto-enumeration of the other key values.

-  // The first entry, whose enum value will be zero, is reserved to mean
-  // no value; there is no corresponding DOM string. (This is not the same
-  // as the valid DOM .key value 'Unidentified'.)
+  // To avoid ambiguities, a small number of .key values that do have
+  // standard names are encoded identical to corresponding Unicode characters;
+  // for example, DomKey('\t') == DomKey::TAB.
+  //
+  //          Key                     Enum        Unicode code point
+  DOM_KEY_UNI("Backspace",            BACKSPACE,  0x0008),
+  DOM_KEY_UNI("Tab",                  TAB,        0x0009),
+  DOM_KEY_UNI("Enter",                ENTER,      0x000D),
+  DOM_KEY_UNI("Escape",               ESCAPE,     0x001B),
+  // The enum constant for 'Delete' (Forward Delete) is named DEL because
+  // DELETE conflicts with an unscoped declaration in Windows' <windows.h>.
+  DOM_KEY_UNI("Delete",               DEL,        0x007F),
 
-  //          Key                     Enum
-  DOM_KEY_MAP(nullptr,                NONE),  // No value
-
-  // A value of DomKey::CHARACTER indicates that the KeyboardEvent |key|
-  // string is determined by the Unicode character interpretation and is
-  // not one of the fixed string values.
-  DOM_KEY_MAP(nullptr,                CHARACTER),
+  DOM_KEY_MAP_BEGIN
 
   // =========================================================
   // Special Key Values
   // http://www.w3.org/TR/DOM-Level-3-Events-key/#keys-special
   // =========================================================
 
   // Unable to identify another key value
   DOM_KEY_MAP("Unidentified",         UNIDENTIFIED),
 
   // ==========================================================
@@ skipping 24 matching lines @@
   // used by such layouts as Neo (German) and Multix (French-Canadian).
   //          Key                     Enum
   DOM_KEY_MAP("ShiftLevel5",          SHIFT_LEVEL5),
 
   // ============================================================
   // Whitespace Keys
   // http://www.w3.org/TR/DOM-Level-3-Events-key/#keys-whitespace
   // ============================================================
 
   //          Key                     Enum
-  DOM_KEY_MAP("Enter",                ENTER),  // Enter, Return
+  //          "Enter" is encoded in the Unicode space (at the end of this list).
   DOM_KEY_MAP("Separator",            SEPARATOR),
-  DOM_KEY_MAP("Tab",                  TAB),
+  //          "Tab" is encoded in the Unicode space.
 
   // ============================================================
   // Navigation Keys
   // http://www.w3.org/TR/DOM-Level-3-Events-key/#keys-navigation
   // ============================================================
 
   //          Key                     Enum
   DOM_KEY_MAP("ArrowDown",            ARROW_DOWN),
   DOM_KEY_MAP("ArrowLeft",            ARROW_LEFT),
   DOM_KEY_MAP("ArrowRight",           ARROW_RIGHT),
   DOM_KEY_MAP("ArrowUp",              ARROW_UP),
   DOM_KEY_MAP("End",                  END),
   DOM_KEY_MAP("Home",                 HOME),
   DOM_KEY_MAP("PageDown",             PAGE_DOWN),
   DOM_KEY_MAP("PageUp",               PAGE_UP),
 
   // =========================================================
   // Editing Keys
   // http://www.w3.org/TR/DOM-Level-3-Events-key/#keys-editing
   // =========================================================
 
   //          Key                     Enum
-  DOM_KEY_MAP("Backspace",            BACKSPACE),
+  //          "Backspace" is encoded in the Unicode space.
   DOM_KEY_MAP("Clear",                CLEAR),
   DOM_KEY_MAP("Copy",                 COPY),
   DOM_KEY_MAP("CrSel",                CR_SEL),     // Cursor Select
   DOM_KEY_MAP("Cut",                  CUT),
-  // Delete (Forward Delete) named DEL because DELETE conflicts with <windows.h>
-  DOM_KEY_MAP("Delete",               DEL),
+  //          "Delete" is encoded in the Unicode space.
   DOM_KEY_MAP("EraseEof",             ERASE_EOF),  // Erase to End of Field
   DOM_KEY_MAP("ExSel",                EX_SEL),     // Extend Selection
   DOM_KEY_MAP("Insert",               INSERT),
   DOM_KEY_MAP("Paste",                PASTE),
   DOM_KEY_MAP("Redo",                 REDO),
   DOM_KEY_MAP("Undo",                 UNDO),
 
   // ====================================================
   // UI Keys
   // http://www.w3.org/TR/DOM-Level-3-Events-key/#keys-ui
   // ====================================================
 
   //          Key                     Enum
   DOM_KEY_MAP("Accept",               ACCEPT),  // Accept current IME conversion
   DOM_KEY_MAP("Again",                AGAIN),   // Repeat an action
   DOM_KEY_MAP("Attn",                 ATTN),    // Attention
   DOM_KEY_MAP("Cancel",               CANCEL),
   DOM_KEY_MAP("ContextMenu",          CONTEXT_MENU),
-  DOM_KEY_MAP("Escape",               ESCAPE),
+  //          "Escape" is encoded in the Unicode space.
   DOM_KEY_MAP("Execute",              EXECUTE),
   DOM_KEY_MAP("Find",                 FIND),
   DOM_KEY_MAP("Help",                 HELP),
   DOM_KEY_MAP("Pause",                PAUSE),  // Program state - not for media
   DOM_KEY_MAP("Play",                 PLAY),   // Program state - not for media
   DOM_KEY_MAP("Props",                PROPS),  // Properties
   DOM_KEY_MAP("Select",               SELECT),
   DOM_KEY_MAP("ZoomIn",               ZOOM_IN),
   DOM_KEY_MAP("ZoomOut",              ZOOM_OUT),
 
@@ skipping 19 matching lines @@
   // IME and Composition Keys
   // http://www.w3.org/TR/DOM-Level-3-Events-key/#keys-composition
   // =============================================================
 
   //          Key                     Enum
   DOM_KEY_MAP("AllCandidates",        ALL_CANDIDATES),
   DOM_KEY_MAP("Alphanumeric",         ALPHANUMERIC),
   DOM_KEY_MAP("CodeInput",            CODE_INPUT),
   DOM_KEY_MAP("Compose",              COMPOSE),
   DOM_KEY_MAP("Convert",              CONVERT),
-  DOM_KEY_MAP("Dead",                 DEAD),
+  //          "Dead" is represented as a flag plus combining character.
   DOM_KEY_MAP("FinalMode",            FINAL_MODE),
   DOM_KEY_MAP("GroupFirst",           GROUP_FIRST),
   DOM_KEY_MAP("GroupLast",            GROUP_LAST),
   DOM_KEY_MAP("GroupNext",            GROUP_NEXT),
   DOM_KEY_MAP("GroupPrevious",        GROUP_PREVIOUS),
   DOM_KEY_MAP("ModeChange",           MODE_CHANGE),
   DOM_KEY_MAP("NextCandidate",        NEXT_CANDIDATE),
   DOM_KEY_MAP("NonConvert",           NON_CONVERT),
   DOM_KEY_MAP("PreviousCandidate",    PREVIOUS_CANDIDATE),
   DOM_KEY_MAP("Process",              PROCESS),
@@ skipping 192 matching lines @@
   DOM_KEY_MAP("STBInput",             STB_INPUT),
   DOM_KEY_MAP("STBPower",             STB_POWER),
   DOM_KEY_MAP("Subtitle",             SUBTITLE),
   DOM_KEY_MAP("Teletext",             TELETEXT),
   DOM_KEY_MAP("TV",                   T_V),
   DOM_KEY_MAP("TVInput",              TV_INPUT),
   DOM_KEY_MAP("TVPower",              TV_POWER),
   DOM_KEY_MAP("VideoModeNext",        VIDEO_MODE_NEXT),
   DOM_KEY_MAP("Wink",                 WINK),
   DOM_KEY_MAP("ZoomToggle",           ZOOM_TOGGLE),
+
+  DOM_KEY_MAP_END
 };