[Origin Trials] Install origin trial bindings on V8 context conditionally

third_party/WebKit/Source/core/workers/WorkerThread.cpp

Index: third_party/WebKit/Source/core/workers/WorkerThread.cpp
diff --git a/third_party/WebKit/Source/core/workers/WorkerThread.cpp b/third_party/WebKit/Source/core/workers/WorkerThread.cpp
index 09d432d27e07d2e84d786d659f64ba7650f45ca3..3df140c7362ec736053bd73ae7e565ecc1c62bbb 100644
--- a/third_party/WebKit/Source/core/workers/WorkerThread.cpp
+++ b/third_party/WebKit/Source/core/workers/WorkerThread.cpp
@@ -33,6 +33,7 @@
 #include "core/inspector/InspectorInstrumentation.h"
 #include "core/inspector/InspectorTaskRunner.h"
 #include "core/inspector/WorkerThreadDebugger.h"
+#include "core/origin_trials/OriginTrialContext.h"
 #include "core/workers/WorkerBackingThread.h"
 #include "core/workers/WorkerClients.h"
 #include "core/workers/WorkerReportingProxy.h"
@@ -345,8 +346,18 @@ void WorkerThread::initializeOnWorkerThread(PassOwnPtr<WorkerThreadStartupData>
         m_workerReportingProxy.workerGlobalScopeStarted(m_workerGlobalScope.get());
 
         WorkerOrWorkletScriptController* scriptController = m_workerGlobalScope->scriptController();
-        if (!scriptController->isExecutionForbidden())
+        if (!scriptController->isExecutionForbidden()) {
             scriptController->initializeContextIfNeeded();
+
+            // If Origin Trials have been registered before the V8 context was ready,

[haraken, 2016/05/27 00:01:42]

I'm just curious but how can we enable origin-trials attributes on workers?
Workers won't have <meta> tags... Is there any special syntax for HTTP headers?

[iclelland, 2016/05/27 03:19:43]

Yes, all resources can now be sent with an HTTP header "origin-trial", which
will also define any tokens to be used for that resource. This is the only way
right now to enable trials on service workers or shared workers.

Dedicated workers can use the HTTP header, and they also inherit any trials that
were enabled by their parent document.

+            // then inject them into the context now
+            ExecutionContext* executionContext = m_workerGlobalScope->getExecutionContext();
+            if (executionContext) {
+                OriginTrialContext* originTrialContext = OriginTrialContext::from(executionContext);
+                if (originTrialContext)
+                    originTrialContext->initializePendingTrials();
+            }
+        }
     }
 
     if (startMode == PauseWorkerGlobalScopeOnStart)