Allow origin trials to be enabled by script

third_party/WebKit/Source/bindings/core/v8/ConditionalFeatures.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "bindings/core/v8/ConditionalFeatures.h"
 
 #include "bindings/core/v8/ScriptState.h"
 #include "bindings/core/v8/V8Document.h"
 #include "bindings/core/v8/V8HTMLLinkElement.h"
 #include "bindings/core/v8/V8Navigator.h"
 #include "bindings/core/v8/V8Window.h"
 #include "core/dom/ExecutionContext.h"
 #include "core/frame/LocalFrame.h"
-#include "core/origin_trials/OriginTrialContext.h"
+#include "core/origin_trials/OriginTrials.h"
 
 namespace blink {
 
 void installConditionalFeaturesCore(const WrapperTypeInfo* wrapperTypeInfo,
                                     const ScriptState* scriptState,
                                     v8::Local<v8::Object> prototypeObject,
                                     v8::Local<v8::Function> interfaceObject) {
   // TODO(iclelland): Generate all of this logic at compile-time, based on the
   // configuration of origin trial enabled attributes and interfaces in IDL
   // files. (crbug.com/615060)
   ExecutionContext* executionContext = scriptState->getExecutionContext();
   if (!executionContext)
     return;
-  OriginTrialContext* originTrialContext = OriginTrialContext::from(
-      executionContext, OriginTrialContext::DontCreateIfNotExists);
   v8::Isolate* isolate = scriptState->isolate();
   const DOMWrapperWorld& world = scriptState->world();
   if (wrapperTypeInfo == &V8HTMLLinkElement::wrapperTypeInfo) {
-    if (RuntimeEnabledFeatures::linkServiceWorkerEnabled() ||
-        (originTrialContext &&
-         originTrialContext->isTrialEnabled("ForeignFetch"))) {
+    if (OriginTrials::linkServiceWorkerEnabled(executionContext)) {
       V8HTMLLinkElement::installLinkServiceWorker(
           isolate, world, v8::Local<v8::Object>(), prototypeObject,
           interfaceObject);
     }
   } else if (wrapperTypeInfo == &V8Window::wrapperTypeInfo) {
     v8::Local<v8::Object> instanceObject = scriptState->context()->Global();
-    if (RuntimeEnabledFeatures::longTaskObserverEnabled() ||
-        (originTrialContext &&
-         originTrialContext->isTrialEnabled("LongTaskObserver"))) {
+    if (OriginTrials::longTaskObserverEnabled(executionContext)) {
       V8Window::installLongTaskObserver(isolate, world, instanceObject,
                                         prototypeObject, interfaceObject);
     }
   } else if (wrapperTypeInfo == &V8Document::wrapperTypeInfo) {
-    if (RuntimeEnabledFeatures::setRootScrollerEnabled() ||
-        (originTrialContext &&
-         originTrialContext->isTrialEnabled("RootScroller"))) {
+    if (OriginTrials::setRootScrollerEnabled(executionContext)) {
       V8Document::installRootScroller(isolate, world, v8::Local<v8::Object>(),
                                       prototypeObject, interfaceObject);
     }
   }
 }
 
+void installPendingConditionalFeatureCore(const String& feature,
+                                          const ScriptState* scriptState) {
+  // TODO(iclelland): Generate all of this logic at compile-time, based on the
+  // configuration of origin trial enabled attributes and interfaces in IDL
+  // files. (crbug.com/615060)
+  v8::Local<v8::Object> prototypeObject;
+  v8::Local<v8::Function> interfaceObject;
+  v8::Isolate* isolate = scriptState->isolate();
+  const DOMWrapperWorld& world = scriptState->world();
+  V8PerContextData* contextData = scriptState->perContextData();
+  if (feature == "ForeignFetch") {

[haraken, 2017/01/28 02:25:20]

How are the features listed in this method selected? In other words, when do
developers need to add a feature to this method?

[chasej, 2017/01/30 19:15:56]

Blink developers will need to update this method upon first integrating their
feature with the origin trials framework. They will also need to update the
InstallConditionalFeatures* method. I will be making updates to the feature
author guide to make this clear, currently found at:
https://github.com/jpchase/OriginTrials/blob/gh-pages/ship-as-trial.md#how-to....

We will eventually automate this via code generation.

+    if (contextData->getExistingConstructorAndPrototypeForType(
+            &V8HTMLLinkElement::wrapperTypeInfo, &prototypeObject,
+            &interfaceObject)) {
+      V8HTMLLinkElement::installLinkServiceWorker(
+          isolate, world, v8::Local<v8::Object>(), prototypeObject,
+          interfaceObject);
+    }
+    return;
+  }
+  if (feature == "LongTaskObserver") {
+    v8::Local<v8::Object> instanceObject = scriptState->context()->Global();
+    V8Window::installLongTaskObserver(isolate, world, instanceObject,
+                                      v8::Local<v8::Object>(),
+                                      v8::Local<v8::Function>());
+    return;
+  }
+  if (feature == "RootScroller") {
+    if (contextData->getExistingConstructorAndPrototypeForType(
+            &V8Document::wrapperTypeInfo, &prototypeObject, &interfaceObject)) {
+      V8Document::installRootScroller(isolate, world, v8::Local<v8::Object>(),
+                                      prototypeObject, interfaceObject);
+    }
+    return;
+  }
+}
+
 namespace {
 
 InstallConditionalFeaturesFunction s_installConditionalFeaturesFunction =
     &installConditionalFeaturesCore;
+
+InstallPendingConditionalFeatureFunction
+    s_installPendingConditionalFeatureFunction =
+        &installPendingConditionalFeatureCore;
 }
 
 InstallConditionalFeaturesFunction setInstallConditionalFeaturesFunction(
     InstallConditionalFeaturesFunction newInstallConditionalFeaturesFunction) {
   InstallConditionalFeaturesFunction originalFunction =
       s_installConditionalFeaturesFunction;
   s_installConditionalFeaturesFunction = newInstallConditionalFeaturesFunction;
   return originalFunction;
 }
 
+InstallPendingConditionalFeatureFunction
+setInstallPendingConditionalFeatureFunction(
+    InstallPendingConditionalFeatureFunction
+        newInstallPendingConditionalFeatureFunction) {
+  InstallPendingConditionalFeatureFunction originalFunction =
+      s_installPendingConditionalFeatureFunction;
+  s_installPendingConditionalFeatureFunction =
+      newInstallPendingConditionalFeatureFunction;
+  return originalFunction;
+}
+
 void installConditionalFeatures(const WrapperTypeInfo* type,
                                 const ScriptState* scriptState,
                                 v8::Local<v8::Object> prototypeObject,
                                 v8::Local<v8::Function> interfaceObject) {
   (*s_installConditionalFeaturesFunction)(type, scriptState, prototypeObject,
                                           interfaceObject);
 }
 
 void installPendingConditionalFeaturesOnWindow(const ScriptState* scriptState) {
   DCHECK(scriptState);
   DCHECK(scriptState->context() == scriptState->isolate()->GetCurrentContext());
   DCHECK(scriptState->perContextData());
   DCHECK(scriptState->world().isMainWorld());
   (*s_installConditionalFeaturesFunction)(&V8Window::wrapperTypeInfo,
                                           scriptState, v8::Local<v8::Object>(),
                                           v8::Local<v8::Function>());
 }
 
+void installPendingConditionalFeature(const String& feature,
+                                      const ScriptState* scriptState) {
+  DCHECK(scriptState);
+  DCHECK(scriptState->context() == scriptState->isolate()->GetCurrentContext());
+  DCHECK(scriptState->perContextData());
+  DCHECK(scriptState->world().isMainWorld());
+
+  (*s_installPendingConditionalFeatureFunction)(feature, scriptState);
+}
+
 bool isFeatureEnabledInFrame(const FeaturePolicy::Feature& feature,
                              const LocalFrame* frame) {
   // If there is no frame, or if feature policy is disabled, use defaults.
   bool enabledByDefault =
       (feature.defaultPolicy == FeaturePolicy::FeatureDefault::EnableForAll ||
        (feature.defaultPolicy == FeaturePolicy::FeatureDefault::EnableForSelf &&
         !frame->isCrossOriginSubframe()));
   if (!RuntimeEnabledFeatures::featurePolicyEnabled() || !frame)
     return enabledByDefault;
   FeaturePolicy* featurePolicy = frame->securityContext()->getFeaturePolicy();
   // The policy should always be initialized before checking it to ensure we
   // properly inherit the parent policy.
   DCHECK(featurePolicy);
 
   // Otherwise, check policy.
   return featurePolicy->isFeatureEnabled(feature);
 }
 
 }  // namespace blink