Move more string_util functions to base namespace.

Rename IsWhitespace to IsUnicodeWhitespace (to contrast it to the already-existing IsAsciiWhitespace).

De-inline HexDigitToInt. This is only used in a few places and I don't think it's necessary to inline.

Remove some redundant base:: qualifications in base.

TBR=sky

Review URL: https://codereview.chromium.org/1200053004

Cr-Original-Commit-Position: refs/heads/master@{#335827}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: b3413064f36bf166d7dffb463bc442059dab1dd7

tools/gn/command_args.cc

diff --git a/tools/gn/command_args.cc b/tools/gn/command_args.cc
index c4c16bb..518a1b6 100644
--- a/tools/gn/command_args.cc
+++ b/tools/gn/command_args.cc
@@ -37,7 +37,7 @@
 bool DoesLineBeginWithComment(const base::StringPiece& line) {
   // Skip whitespace.
   size_t i = 0;
-  while (i < line.size() && IsAsciiWhitespace(line[i]))
+  while (i < line.size() && base::IsAsciiWhitespace(line[i]))
     i++;
 
   return i < line.size() && line[i] == '#';

tools/gn/filesystem_utils.cc

diff --git a/tools/gn/filesystem_utils.cc b/tools/gn/filesystem_utils.cc
index 67bb6e2..6e1c01d 100644
--- a/tools/gn/filesystem_utils.cc
+++ b/tools/gn/filesystem_utils.cc
@@ -100,7 +100,7 @@
     return false;
 
   // Check drive letter.
-  if (!IsAsciiAlpha(path[0]))
+  if (!base::IsAsciiAlpha(path[0]))
     return false;
 
   if (!IsSlash(path[2]))

tools/gn/label.cc

diff --git a/tools/gn/label.cc b/tools/gn/label.cc
index 60ebf31..171511a 100644
--- a/tools/gn/label.cc
+++ b/tools/gn/label.cc
@@ -105,7 +105,7 @@
       return false;
     }
     if (input.size() > 3 && input[2] == ':' && IsSlash(input[3]) &&
-        IsAsciiAlpha(input[1])) {
+        base::IsAsciiAlpha(input[1])) {
       // Skip over the drive letter colon.
       offset = 3;
     }

tools/gn/label_pattern.cc

diff --git a/tools/gn/label_pattern.cc b/tools/gn/label_pattern.cc
index e5ea5cf..6c8addd 100644
--- a/tools/gn/label_pattern.cc
+++ b/tools/gn/label_pattern.cc
@@ -132,7 +132,7 @@
       return LabelPattern();
     }
     if (str.size() > 3 && str[2] == ':' && IsSlash(str[3]) &&
-        IsAsciiAlpha(str[1])) {
+        base::IsAsciiAlpha(str[1])) {
       // Skip over the drive letter colon.
       offset = 3;
     }

tools/gn/tokenizer.cc

diff --git a/tools/gn/tokenizer.cc b/tools/gn/tokenizer.cc
index 567fa72..be3223b 100644
--- a/tools/gn/tokenizer.cc
+++ b/tools/gn/tokenizer.cc
@@ -188,7 +188,7 @@
 Token::Type Tokenizer::ClassifyCurrent() const {
   DCHECK(!at_end());
   char next_char = cur_char();
-  if (IsAsciiDigit(next_char))
+  if (base::IsAsciiDigit(next_char))
     return Token::INTEGER;
   if (next_char == '"')
     return Token::STRING;
@@ -228,7 +228,7 @@
       return Token::UNCLASSIFIED_OPERATOR;  // Just the minus before end of
                                             // file.
     char following_char = input_[cur_ + 1];
-    if (IsAsciiDigit(following_char))
+    if (base::IsAsciiDigit(following_char))
       return Token::INTEGER;
     return Token::UNCLASSIFIED_OPERATOR;
   }
@@ -242,7 +242,7 @@
     case Token::INTEGER:
       do {
         Advance();
-      } while (!at_end() && IsAsciiDigit(cur_char()));
+      } while (!at_end() && base::IsAsciiDigit(cur_char()));
       if (!at_end()) {
         // Require the char after a number to be some kind of space, scope,
         // or operator.

tools/gn/tokenizer.h

diff --git a/tools/gn/tokenizer.h b/tools/gn/tokenizer.h
index 497a170..29d107a 100644
--- a/tools/gn/tokenizer.h
+++ b/tools/gn/tokenizer.h
@@ -33,12 +33,12 @@
   static bool IsNewline(const base::StringPiece& buffer, size_t offset);
 
   static bool IsIdentifierFirstChar(char c) {
-    return IsAsciiAlpha(c) || c == '_';
+    return base::IsAsciiAlpha(c) || c == '_';
   }
 
   static bool IsIdentifierContinuingChar(char c) {
     // Also allow digits after the first char.
-    return IsIdentifierFirstChar(c) || IsAsciiDigit(c);
+    return IsIdentifierFirstChar(c) || base::IsAsciiDigit(c);
   }
 
  private: