Cleanup IFX_BidiChar

core/include/fxcrt/fx_arb.h

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #ifndef CORE_INCLUDE_FXCRT_FX_ARB_H_
 #define CORE_INCLUDE_FXCRT_FX_ARB_H_
 
 #include "fx_system.h"
 
+// Processes characters and group them into segments based on text direction.
 class IFX_BidiChar
 {
 public:
+    enum Direction {
+      NEUTRAL,
+      LEFT,
+      RIGHT
+    };
+
     static IFX_BidiChar* Create();
     virtual ~IFX_BidiChar() {}
 
-    virtual void SetPolicy(FX_BOOL bSeparateNeutral = TRUE) = 0;
-    virtual FX_BOOL AppendChar(FX_WCHAR wch) = 0;
-    virtual FX_BOOL EndChar() = 0;
-    virtual int32_t GetBidiInfo(int32_t &iStart, int32_t &iCount) = 0;
-    virtual void Reset() = 0;
+    // Append a character and classify it as left, right, or neutral.
+    // Returns true if the character has a different direction than the
+    // existing direction to indicate there is a segment to process.
+    virtual bool AppendChar(FX_WCHAR wch) = 0;
+
+    // Call this after the last character has been appended. AppendChar()
+    // should not be called after this.

[Tom Sepez, 2015/06/19 20:30:32]

nit: "may not" or "must not".

[Lei Zhang, 2015/08/17 17:41:35]

Done.

+    // Returns if there is still a segment to process.
+    virtual bool EndChar() = 0;

[Tom Sepez, 2015/06/19 20:30:32]

nit: it's still a mystery -- returns what?

[Lei Zhang, 2015/08/17 17:41:35]

Done.

+
+    // Get information about the segment to process.
+    // The segment's start position and character count goes in |iStart| and

[Tom Sepez, 2015/06/19 20:30:32]

nit: s/goes in/is returned in/

[Lei Zhang, 2015/08/17 17:41:35]

Done.

+    // |iCount|, respectively. Pass in null pointers if the information is not
+    // needed.
+    // Returns the segment direction.
+    virtual Direction GetBidiInfo(int32_t* iStart, int32_t* iCount) = 0;
 };
 
 #endif  // CORE_INCLUDE_FXCRT_FX_ARB_H_