Reland: Do not initialize |v8::Context| on |ScriptController::updateDocument|.

> The reason for reverting is: broke interactive_ui_tests:
> 
> Referrer
> SearchReusesInstantTab
> TypedSearchURLDoesntReuseInstantTab.
I fixed these tests in https://src.chromium.org/viewvc/chrome?view=rev&revision=273996 .

Original Description:

Initializing |v8::Context| is a heavy operation, and should be avoided if necessary. This is meant to be delayed until first time |toV8Context| is called, but |ScriptController::updateDocument| was forcing creation.

This patch fixes the if branch so that it would not create a |v8::Context| if it does not exist.

BUG=368548, 368555

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=173044

Review URL: https://codereview.chromium.org/263583002

git-svn-id: svn://svn.chromium.org/blink/trunk@175240 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/bindings/v8/ScriptController.cpp

@@ -465,8 +465,8 @@ int ScriptController::contextDebugId(v8::Handle<v8::Context> context)
 
 void ScriptController::updateDocument()
 {
-    // For an uninitialized main window shell, do not incur the cost of context initialization during FrameLoader::init().
-    if ((!m_windowShell->isContextInitialized() || !m_windowShell->isGlobalInitialized()) && m_frame->loader().stateMachine()->creatingInitialEmptyDocument())
+    // For an uninitialized main window shell, do not incur the cost of context initialization.
+    if (!m_windowShell->isGlobalInitialized())
         return;
 
     if (!initializeMainWorld())

third_party/WebKit/Source/core/testing/v8/WebCoreTestSupport.cpp

@@ -41,6 +41,10 @@ namespace WebCoreTestSupport {
 
 void injectInternalsObject(v8::Local<v8::Context> context)
 {
+    // This can happen if no JavaScript was used in the main frame.
+    if (context.IsEmpty())
+        return;
+
     v8::Context::Scope contextScope(context);
     v8::HandleScope scope(context->GetIsolate());
     ExecutionContext* scriptContext = currentExecutionContext(context->GetIsolate());