Cache csi info before passing it to JS setters.

chrome/renderer/loadtimes_extension_bindings.cc

 // Copyright (c) 2012 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 "chrome/renderer/loadtimes_extension_bindings.h"
 
 #include <math.h>
 
 #include "base/time/time.h"
 #include "content/public/renderer/document_state.h"
@@ skipping 152 matching lines @@
     load_times->Set(
         v8::String::NewFromUtf8(isolate, "wasAlternateProtocolAvailable"),
         v8::Boolean::New(isolate, was_alternate_protocol_available));
     load_times->Set(v8::String::NewFromUtf8(isolate, "connectionInfo"),
                     v8::String::NewFromUtf8(isolate, connection_info.c_str()));
     args.GetReturnValue().Set(load_times);
   }
 
   static void GetCSI(const v8::FunctionCallbackInfo<v8::Value>& args) {
     WebLocalFrame* frame = WebLocalFrame::frameForCurrentContext();
-    if (frame) {
-      WebDataSource* data_source = frame->dataSource();
-      if (data_source) {
-        DocumentState* document_state =
-            DocumentState::FromDataSource(data_source);
-        v8::Isolate* isolate = args.GetIsolate();
-        v8::Local<v8::Object> csi = v8::Object::New(isolate);
-        base::Time now = base::Time::Now();
-        base::Time start = document_state->request_time().is_null() ?
-            document_state->start_load_time() :
-            document_state->request_time();
-        base::Time onload = document_state->finish_document_load_time();
-        base::TimeDelta page = now - start;
-        csi->Set(v8::String::NewFromUtf8(isolate, "startE"),
-                 v8::Number::New(isolate, floor(start.ToDoubleT() * 1000)));
-        csi->Set(v8::String::NewFromUtf8(isolate, "onloadT"),
-                 v8::Number::New(isolate, floor(onload.ToDoubleT() * 1000)));
-        csi->Set(v8::String::NewFromUtf8(isolate, "pageT"),
-                 v8::Number::New(isolate, page.InMillisecondsF()));
-        csi->Set(
-            v8::String::NewFromUtf8(isolate, "tran"),
-            v8::Number::New(
-                isolate, GetCSITransitionType(data_source->navigationType())));
-
-        args.GetReturnValue().Set(csi);
-        return;
-      }
+    if (!frame) {
+      args.GetReturnValue().SetNull();
+      return;
     }
-    args.GetReturnValue().SetNull();
-    return;
+    WebDataSource* data_source = frame->dataSource();
+    if (!data_source) {
+      args.GetReturnValue().SetNull();
+      return;
+    }
+    DocumentState* document_state = DocumentState::FromDataSource(data_source);
+    if (!document_state) {
+      args.GetReturnValue().SetNull();
+      return;
+    }
+    base::Time now = base::Time::Now();
+    base::Time start = document_state->request_time().is_null()
+                           ? document_state->start_load_time()
+                           : document_state->request_time();
+    base::Time onload = document_state->finish_document_load_time();
+    base::TimeDelta page = now - start;
+    int navigation_type = GetCSITransitionType(data_source->navigationType());
+    // Important: |frame|, |data_source| and |document_state| should not be
+    // referred to below this line, as JS setters below can invalidate these
+    // pointers.
+    v8::Isolate* isolate = args.GetIsolate();
+    v8::Local<v8::Object> csi = v8::Object::New(isolate);
+    csi->Set(v8::String::NewFromUtf8(isolate, "startE"),

[jochen (gone - plz use gerrit), 2016/03/02 10:48:31]

please use the non-deprecated versions:

v8::Local<v8::Context> ctx = isolate->GetCurrentContext();
if (!csi->Set(ctx, v8::String::NewFromUtf8(isolate, "startE",
v8::NewStringType::kNormal).ToLocalChecked()).FromMaybe(false))
  return;

[meacer, 2016/03/02 20:46:36]

Done.

+             v8::Number::New(isolate, floor(start.ToDoubleT() * 1000)));
+    csi->Set(v8::String::NewFromUtf8(isolate, "onloadT"),
+             v8::Number::New(isolate, floor(onload.ToDoubleT() * 1000)));
+    csi->Set(v8::String::NewFromUtf8(isolate, "pageT"),
+             v8::Number::New(isolate, page.InMillisecondsF()));
+    csi->Set(v8::String::NewFromUtf8(isolate, "tran"),
+             v8::Number::New(isolate, navigation_type));
+    args.GetReturnValue().Set(csi);
   }
 };
 
 v8::Extension* LoadTimesExtension::Get() {
   return new LoadTimesExtensionWrapper();
 }
 
 }  // namespace extensions_v8