Teach WebString about 8 bit strings

public/platform/WebString.h

Index: public/platform/WebString.h
diff --git a/public/platform/WebString.h b/public/platform/WebString.h
index c336dd113dcd61aefae52a9808b6c57275f3b9df..d85c10b5be16b0921510ea2d84b6ed467b6c8b80 100644
--- a/public/platform/WebString.h
+++ b/public/platform/WebString.h
@@ -76,6 +76,7 @@ public:
     WEBKIT_EXPORT bool equals(const WebString& s) const;
 
     WEBKIT_EXPORT size_t length() const;
+    // Deprecated: This function will be removed once all its callers are gone.
     WEBKIT_EXPORT const WebUChar* data() const;
 
     bool isEmpty() const { return !length(); }
@@ -122,7 +123,14 @@ public:
     operator string16() const
     {
         size_t len = length();

[darin (slow to review), 2013/05/24 06:12:53]

nit: this seems like a lot of code to inline into all of the callsites where
casting to string16 is required.  perhaps a higher level non-inline method would
be helpful.  hmm, but you are calling two different string16 constructors below.
 hmm...

-        return len ? string16(data(), len) : string16();
+        if (!len)
+            return string16();
+        if (is8Bit()) {
+            const WebLChar* data = this->data8();
+            return string16(data, data + len);
+        }
+        const WebUChar* data = this->data16();
+        return string16(data, data + len);
     }
 
     WebString(const NullableString16& s) : m_private(0)
@@ -146,8 +154,7 @@ public:
     {
         if (!m_private)
             return NullableString16(string16(), true);
-        size_t len = length();
-        return NullableString16(len ? string16(data(), len) : string16(), false);
+        return NullableString16(operator string16(), false);

[darin (slow to review), 2013/05/24 06:12:53]

nit: You could reduce this code down to just:

  return NullableString16(operator string16(), isNull());

[abarth-chromium, 2013/05/24 06:17:44]

Good idea.

     }
 
     template <class UTF8String>
@@ -158,6 +165,10 @@ public:
 #endif
 
 private:
+    WEBKIT_EXPORT bool is8Bit() const;
+    WEBKIT_EXPORT const WebLChar* data8() const;
+    WEBKIT_EXPORT const WebUChar* data16() const;
+
     void assign(WebStringPrivate*);
     WebStringPrivate* m_private;
 };