Support loading trial tokens from HTTP headers.

third_party/WebKit/Source/build/scripts/templates/OriginTrials.cpp.tmpl

Index: third_party/WebKit/Source/build/scripts/templates/OriginTrials.cpp.tmpl
diff --git a/third_party/WebKit/Source/build/scripts/templates/OriginTrials.cpp.tmpl b/third_party/WebKit/Source/build/scripts/templates/OriginTrials.cpp.tmpl
index 5cad45d87a96ae41766e9728fc710756e5818cd5..ec51e8cdfcccdc10a529e90c37c3076d16dc07d0 100644
--- a/third_party/WebKit/Source/build/scripts/templates/OriginTrials.cpp.tmpl
+++ b/third_party/WebKit/Source/build/scripts/templates/OriginTrials.cpp.tmpl
@@ -28,6 +28,13 @@ OriginTrials* OriginTrials::from(ExecutionContext* host)
 OriginTrials::OriginTrials(ExecutionContext* host)
     : OriginTrialsBase(host) {}
 
+// static
+void OriginTrials::setTrialTokensFromHeader(ExecutionContext* executionContext, const String& headerValue)
+{
+    if (headerValue.isEmpty()) return;

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

I don't know how much we care about formatting in generated code, but if I try
this in a blink cpp file, the presubmit hooks make me move the return to another
line.

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

Yeah, was already fixed in the patch I uploaded yesterday (by no longer
modifying any of the generated code).

+    from(executionContext)->loadTokensFromHeader(headerValue);
+}
+
 {% for feature in features %}
 {% if feature.origin_trial_feature_name %}