Begin to enable extension APIs in Extension Service Worker.

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

Index: third_party/WebKit/Source/bindings/core/v8/WorkerOrWorkletScriptController.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/WorkerOrWorkletScriptController.cpp b/third_party/WebKit/Source/bindings/core/v8/WorkerOrWorkletScriptController.cpp
index 43079ab58290e3addff5e4aa65172b9316a6168e..ce347447de4e3ee679c02066e444adc88e40a86b 100644
--- a/third_party/WebKit/Source/bindings/core/v8/WorkerOrWorkletScriptController.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/WorkerOrWorkletScriptController.cpp
@@ -31,6 +31,7 @@
 #include "bindings/core/v8/WorkerOrWorkletScriptController.h"
 
 #include "bindings/core/v8/ScriptCallStack.h"
+#include "bindings/core/v8/ScriptController.h"
 #include "bindings/core/v8/ScriptSourceCode.h"
 #include "bindings/core/v8/ScriptValue.h"
 #include "bindings/core/v8/V8DedicatedWorkerGlobalScope.h"
@@ -51,6 +52,7 @@
 #include "core/workers/WorkerThread.h"
 #include "platform/heap/ThreadState.h"
 #include "public/platform/Platform.h"
+#include "wtf/Threading.h"
 #include <v8.h>
 
 namespace blink {
@@ -107,6 +109,17 @@ WorkerOrWorkletScriptController* WorkerOrWorkletScriptController::create(WorkerO
     return new WorkerOrWorkletScriptController(globalScope, isolate);
 }
 
+void WorkerOrWorkletScriptController::registerExtensionIfNeeded(v8::Extension* extension)
+{
+    const V8Extensions& extensions = registeredExtensions();
+    for (size_t i = 0; i < extensions.size(); ++i) {
+        if (extensions[i] == extension)
+            return;
+    }
+    v8::RegisterExtension(extension);
+    registeredExtensions().append(extension);

[haraken, 2016/04/19 04:24:57]

Can we add an assert to check that this is a ScriptController for ServiceWorker?
We don't want to allow any extension for normal workers.

[lazyboy, 2016/04/20 02:26:54]

How do I do that? Note that this is a static method.

+}
+
 WorkerOrWorkletScriptController::WorkerOrWorkletScriptController(WorkerOrWorkletGlobalScope* globalScope, v8::Isolate* isolate)
     : m_globalScope(globalScope)
     , m_isolate(isolate)
@@ -156,7 +169,14 @@ bool WorkerOrWorkletScriptController::initializeContextIfNeeded()
     if (isContextInitialized())
         return true;
 
-    v8::Local<v8::Context> context = v8::Context::New(m_isolate);
+    // Initialize V8 extensions before creating the context.
+    Vector<const char*> extensionNames;
+    const V8Extensions& extensions = registeredExtensions();
+    extensionNames.reserveInitialCapacity(extensions.size());
+    for (const auto* extension : extensions)
+        extensionNames.append(extension->name());

[haraken, 2016/04/19 04:24:57]

Just to confirm: You're unconditionally enabling all extensions here -- this is
intentional, right?

c.f., The main world enables only extensions that meet
associatedFrame->loader().client()->allowScriptExtension().

[lazyboy, 2016/04/20 02:26:54]

Yes, I had to do this unconditionally. (I also got fooled by it at first
thinking allowScriptExtension() always returns true, except EmptyClients, which
I mistakenly thought were only for tests).

I don't however know what the implication of unconditionally turning this on is.
One way could be to try to ask the embedder the same way as FrameLoaderClient
does.

Also, should we at guard setting |extensionNames| with if
(m_globalScope->isServiceWorkerGlobalScope()) ?

WDYT?

[haraken, 2016/04/20 04:24:56]

Yes, we *must* do this. Otherwise, the extensions will be enable on normal
workers as well.

BTW, is the set of extensions installed on ScriptController different from the
set of extensions installed on WorkerOrWorkletScriptController? In other words,
do you have different sets of extensions for the main page and the service
worker?

I think the answer should be no. If so, we should remove
WorkerOrWorkletScriptController::extensions and instead just use
ScriptController::extensions.

[lazyboy, 2016/04/21 05:52:15]

I have guarded the extension installation by checking whether this has a 
ServiceWorker GlobalScope.
When I run and print ScriptController::registeredExtensions() for debugging, I
get the following 3, where I would have expected only the SafeBuiltins one:
extensions::SafeBuiltins
v8/External
v8/LoadTimes

Since WorkerOrWorkerScriptController::registeredExtensions() is only
accessed/read in worker thread, isn't using
ScriptController::registeredExtensions() non-thread safe as someone can add more
stuff to it, possibly from main renderer?

If I use ScriptController::registeredExtensions() here, extension service
workers work, but regular web service worker renderer crashes. I haven't figured
out the exact details here.

Also, based on falken@'s comment, I've restricted populating
WorkerOrWorkletScriptController::registeredExtensions() to only for chrome
extension service workers, not for web service workers.

+    v8::ExtensionConfiguration extensionConfiguration(extensionNames.size(), extensionNames.data());
+    v8::Local<v8::Context> context = v8::Context::New(m_isolate, &extensionConfiguration);
     if (context.IsEmpty())
         return false;
 
@@ -192,6 +212,13 @@ bool WorkerOrWorkletScriptController::initializeContextIfNeeded()
     return v8CallBoolean(globalObject->SetPrototype(context, jsGlobalScope));
 }
 
+V8Extensions& WorkerOrWorkletScriptController::registeredExtensions()

[haraken, 2016/04/19 04:24:57]

Move this method to just above registerExtensionIfNeeded.

[lazyboy, 2016/04/20 02:26:54]

Done.

+{
+    // Accessed from worker threads.
+    DEFINE_THREAD_SAFE_STATIC_LOCAL(V8Extensions, extensions, new V8Extensions);
+    return extensions;
+}
+
 ScriptValue WorkerOrWorkletScriptController::evaluate(const CompressibleString& script, const String& fileName, const TextPosition& scriptStartPosition, CachedMetadataHandler* cacheHandler, V8CacheOptions v8CacheOptions)
 {
     if (!initializeContextIfNeeded())