Support loading trial tokens from HTTP headers.

third_party/WebKit/Source/core/origin_trials/OriginTrialsBase.cpp

Index: third_party/WebKit/Source/core/origin_trials/OriginTrialsBase.cpp
diff --git a/third_party/WebKit/Source/core/origin_trials/OriginTrialsBase.cpp b/third_party/WebKit/Source/core/origin_trials/OriginTrialsBase.cpp
index 2c13003ab0cee7f233afe2ebfd7e877a55263f56..5feaa2ba6dabf3c57b5f536ab52eb27cdeb67cb5 100644
--- a/third_party/WebKit/Source/core/origin_trials/OriginTrialsBase.cpp
+++ b/third_party/WebKit/Source/core/origin_trials/OriginTrialsBase.cpp
@@ -35,6 +35,14 @@ void OriginTrialsBase::addToken(const String& token)
     m_tokens.append(token);
 }
 
+void OriginTrialsBase::loadTokensFromHeader(const String& headerValue)
+{
+    Vector<String> headers;
+    headerValue.split(',', headers);

[iclelland, 2016/04/05 17:01:30]

Is there a method which takes into account quoted strings? This makes ',' a
reserved character which can't appear in a token now. (Which is probably fine,
as long as we document it, 

[Marijn Kruisselbrink, 2016/04/05 23:57:00]

Ah, good point. In the spec I started writing I even explicitly allowed quoted
and unquoted tokens, which this code doesn't handle at all. Should probably use
net::HttpUtil::ValuesIterator, but that's tricky because blink doesn't (yet?)
depend on net (and it seems every part of blink that parses headers mostly rolls
their own implementation, and mostly gets quoted strings wrong afaict). I added
wrappers around some net::HttpUtil methods in blink
platform/network/HTTPParsers, and used those here. Hopefully blink platform
owners are happy with something like this.

+    for (const String& header : headers)
+        addToken(header.stripWhiteSpace());
+}
+
 DEFINE_TRACE(OriginTrialsBase)
 {
     visitor->trace(m_host);