Added --force-ui-direction flag for developers to force LTR or RTL.

base/i18n/rtl.cc

 // Copyright (c) 2011 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.
 
 #include "base/i18n/rtl.h"
 
 #include <algorithm>
 
+#include "base/command_line.h"
 #include "base/files/file_path.h"
+#include "base/i18n/base_i18n_switches.h"
 #include "base/logging.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "third_party/icu/source/common/unicode/locid.h"
 #include "third_party/icu/source/common/unicode/uchar.h"
 #include "third_party/icu/source/common/unicode/uscript.h"
 #include "third_party/icu/source/i18n/unicode/coll.h"
 
@@ skipping 37 matching lines @@
       (property == U_RIGHT_TO_LEFT_OVERRIDE)) {
     return base::i18n::RIGHT_TO_LEFT;
   } else if ((property == U_LEFT_TO_RIGHT) ||
              (property == U_LEFT_TO_RIGHT_EMBEDDING) ||
              (property == U_LEFT_TO_RIGHT_OVERRIDE)) {
     return base::i18n::LEFT_TO_RIGHT;
   }
   return base::i18n::UNKNOWN_DIRECTION;
 }
 
+// Gets the explicitly forced text direction for debugging. If no forcing is
+// applied, returns UNKNOWN_DIRECTION.
+base::i18n::TextDirection GetForcedTextDirection() {
+  // On iOS, check for RTL forcing.
+#if defined(OS_IOS)
+  if (base::ios::IsInForcedRTL())
+    return base::i18n::RIGHT_TO_LEFT;
+#endif
+
+  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+  if (command_line->HasSwitch(switches::kForceUIDirection)) {
+    std::string force_flag =
+        command_line->GetSwitchValueASCII(switches::kForceUIDirection);
+
+    if (force_flag == switches::kForceUIDirectionLTR)
+      return base::i18n::LEFT_TO_RIGHT;
+
+    if (force_flag == switches::kForceUIDirectionRTL)
+      return base::i18n::RIGHT_TO_LEFT;
+  }
+
+  return base::i18n::UNKNOWN_DIRECTION;
+}
+
 }  // namespace
 
 namespace base {
 namespace i18n {
 
 // Represents the locale-specific ICU text direction.
 static TextDirection g_icu_text_direction = UNKNOWN_DIRECTION;
 
 // Convert the ICU default locale to a string.
 std::string GetConfiguredLocale() {
@@ skipping 51 matching lines @@
 
 bool ICUIsRTL() {
   if (g_icu_text_direction == UNKNOWN_DIRECTION) {
     const icu::Locale& locale = icu::Locale::getDefault();
     g_icu_text_direction = GetTextDirectionForLocaleInStartUp(locale.getName());
   }
   return g_icu_text_direction == RIGHT_TO_LEFT;
 }
 
 TextDirection GetTextDirectionForLocaleInStartUp(const char* locale_name) {
-// On iOS, check for RTL forcing.
-#if defined(OS_IOS)
-  if (ios::IsInForcedRTL())
-    return RIGHT_TO_LEFT;
-#endif
+  // Check for direction forcing.
+  TextDirection forced_direction = GetForcedTextDirection();
+  if (forced_direction != UNKNOWN_DIRECTION)
+    return forced_direction;
 
   // This list needs to be updated in alphabetical order if we add more RTL
   // locales.
   static const char* kRTLLanguageCodes[] = {"ar", "fa", "he", "iw", "ur"};
   std::vector<StringPiece> locale_split =
       SplitStringPiece(locale_name, "-_", KEEP_WHITESPACE, SPLIT_WANT_ALL);
   const StringPiece& language_code = locale_split[0];
   if (std::binary_search(kRTLLanguageCodes,
                          kRTLLanguageCodes + arraysize(kRTLLanguageCodes),
                          language_code))
     return RIGHT_TO_LEFT;
   return LEFT_TO_RIGHT;
 }
 
 TextDirection GetTextDirectionForLocale(const char* locale_name) {
-  // On iOS, check for RTL forcing.
-#if defined(OS_IOS)
-  if (ios::IsInForcedRTL())
-    return RIGHT_TO_LEFT;
-#endif
+  // Check for direction forcing.
+  TextDirection forced_direction = GetForcedTextDirection();
+  if (forced_direction != UNKNOWN_DIRECTION)
+    return forced_direction;
 
   UErrorCode status = U_ZERO_ERROR;
   ULayoutType layout_dir = uloc_getCharacterOrientation(locale_name, &status);
   DCHECK(U_SUCCESS(status));
   // Treat anything other than RTL as LTR.
   return (layout_dir != ULOC_LAYOUT_RTL) ? LEFT_TO_RIGHT : RIGHT_TO_LEFT;
 }
 
 TextDirection GetFirstStrongCharacterDirection(const string16& text) {
   const UChar* string = text.c_str();
@@ skipping 242 matching lines @@
       begin == kRightToLeftOverride)
     ++begin_index;
   size_t end_index = text.length() - 1;
   if (text[end_index] == kPopDirectionalFormatting)
     --end_index;
   return text.substr(begin_index, end_index - begin_index + 1);
 }
 
 }  // namespace i18n
 }  // namespace base