Fix DevTools support of worklets

third_party/WebKit/Source/core/inspector/MainThreadDebugger.cpp

Index: third_party/WebKit/Source/core/inspector/MainThreadDebugger.cpp
diff --git a/third_party/WebKit/Source/core/inspector/MainThreadDebugger.cpp b/third_party/WebKit/Source/core/inspector/MainThreadDebugger.cpp
index c5231f3773fa64d14dffbbc95a5f4dbf01dd43f0..f604ff92ed78ab8d0d5b621533f0c8655ade7d05 100644
--- a/third_party/WebKit/Source/core/inspector/MainThreadDebugger.cpp
+++ b/third_party/WebKit/Source/core/inspector/MainThreadDebugger.cpp
@@ -112,6 +112,7 @@ void MainThreadDebugger::contextCreated(ScriptState* scriptState, LocalFrame* fr
     ASSERT(isMainThread());
     v8::HandleScope handles(scriptState->isolate());
     DOMWrapperWorld& world = scriptState->world();
+    DLOG(WARNING) << toDOMWindow(scriptState->isolate()->GetCallingContext());
     debugger()->contextCreated(V8ContextInfo(scriptState->context(), contextGroupId(frame), world.isMainWorld(), origin ? origin->toRawString() : "", world.isIsolatedWorld() ? world.isolatedWorldHumanReadableName() : "", IdentifiersFactory::frameId(frame), scriptState->getExecutionContext()->isDocument()));
 }
 
@@ -194,7 +195,14 @@ bool MainThreadDebugger::callingContextCanAccessContext(v8::Local<v8::Context> c
 
     if (executionContext->isMainThreadWorkletGlobalScope()) {
         MainThreadWorkletGlobalScope* globalScope = toMainThreadWorkletGlobalScope(executionContext);
-        return globalScope && BindingSecurity::shouldAllowAccessTo(m_isolate, toLocalDOMWindow(toDOMWindow(calling)), globalScope, DoNotReportSecurityError);
+        DLOG(WARNING) << toLocalDOMWindow(toDOMWindow(calling));
+        DLOG(WARNING) << toLocalDOMWindow(toDOMWindow(target));
+        if (globalScope) {

[dgozman, 2016/06/24 22:03:15]

This code only runs if |target| is a worklet. You should move it outside of if
statement.

[Gleb Lanbin, 2016/06/25 00:17:26]

not sure if it helps. In my case when I stop inside of the worklet |calling| is
the context of my worklet function that doesn't have DOM window associated with
it and I'm not sure what is the |target| in my case. I think |target| is my main
CSS paint function defined in CSSPaintDefinition.cpp. It doesn't have DOM window
as well.

Maybe I should just verify that |target| and |calling| are running in
MainThreadWorkletGlobalScope execution context and let it go?
Something like

if (toExecutionContext(target).isMainThreadWorkletGlobalScope() &&
toExecutionContext(calling).isMainThreadWorkletGlobalScope()) return true;
what do you think?

[dgozman, 2016/06/27 21:16:41]

Take a look at how BindingSecurity::shouldAllowAccessTo retrieves a frame and
then DOM window from a worklet.
No, in this case we should check that worklets are from the frames which can
script each other.
We cannot skip security checks.

+            bool isAllowedToWorklet = BindingSecurity::shouldAllowAccessTo(m_isolate, toLocalDOMWindow(toDOMWindow(calling)), globalScope, DoNotReportSecurityError);
+            bool isAllowedFromWorklet = BindingSecurity::shouldAllowAccessTo(m_isolate, toLocalDOMWindow(toDOMWindow(target)), globalScope, DoNotReportSecurityError);
+            return isAllowedToWorklet || isAllowedFromWorklet;
+        }
+        return false;
     }
 
     DOMWindow* window = toDOMWindow(target);