Fix "report the exception" in Custom Elements V1

third_party/WebKit/Source/bindings/core/v8/V8ScriptRunner.cpp

Index: third_party/WebKit/Source/bindings/core/v8/V8ScriptRunner.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8ScriptRunner.cpp b/third_party/WebKit/Source/bindings/core/v8/V8ScriptRunner.cpp
index 2485dc2cc6f7846ab327bec575bf0c1116872a49..d99a1b39b617955906c2502c729463008490b69e 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8ScriptRunner.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/V8ScriptRunner.cpp
@@ -588,4 +588,25 @@ void V8ScriptRunner::setCacheTimeStamp(CachedMetadataHandler* cacheHandler)
     cacheHandler->setCachedMetadata(tag, reinterpret_cast<char*>(&now), sizeof(now), CachedMetadataHandler::SendToPlatform);
 }
 
+void V8ScriptRunner::throwException(v8::Isolate* isolate, v8::Local<v8::Value> exception, const v8::ScriptOrigin& origin)
+{
+    // Use V8ThrowException instead of this function unless absolutely needed.

[Yuki, 2016/08/22 06:42:08]

Thanks for the caution, but it's better to put this caution in .h file.

+    // In order for the current TryCatch to catch this exception and
+    // call MessageCallback when SetVerbose(true), create a v8::Function
+    // that calls isolate->throwException().
+    // Unlike throwStackOverflowExceptionIfNeeded(), create a temporary Script
+    // with the specified ScriptOrigin. When the exception was created but not
+    // thrown yet, the ScriptOrigin of the thrower is set to the exception.
+    // v8::Function::New() has empty ScriptOrigin, and thus the exception will
+    // be "muted" (sanitized in our terminology) if CORS does not allow.
+    // https://html.spec.whatwg.org/multipage/webappapis.html#report-the-error
+    v8::Local<v8::Script> script = compileWithoutOptions(
+        V8CompileHistogram::Cacheability::Noncacheable, isolate,
+        v8AtomicString(isolate, "((e) => { throw e; })"), origin)
+        .ToLocalChecked();
+    v8::Local<v8::Function> thrower = runCompiledInternalScript(isolate, script)

[haraken, 2016/08/22 06:36:47]

It's silly that we have to compile the script every time. We should introduce a
V8 API that enables us to set a ScriptOrigin on v8::Function. Would you file a
bug and add a TODO?

+        .ToLocalChecked().As<v8::Function>();
+    callInternalFunction(thrower, thrower, 1, &exception, isolate);

[haraken, 2016/08/22 06:36:47]

I'd prefer creating an array.

v8::Local<v8::Value> args = { exception };
callInternalFunction(..., WTF_ARRAY_LENGTH(args), args, ...);

+}
+
 } // namespace blink