Makes mojo WebUI run main only after page finishes loading

content/renderer/web_ui_mojo.cc

 // Copyright 2014 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 "content/renderer/web_ui_mojo.h"
 
 #include "content/common/view_messages.h"
 #include "content/public/renderer/render_frame.h"
 #include "content/public/renderer/render_view.h"
 #include "content/renderer/web_ui_mojo_context_state.h"
@@ skipping 23 matching lines @@
 
 WebUIMojo::MainFrameObserver::~MainFrameObserver() {
 }
 
 void WebUIMojo::MainFrameObserver::WillReleaseScriptContext(
     v8::Handle<v8::Context> context,
     int world_id) {
   web_ui_mojo_->DestroyContextState(context);
 }
 
+void WebUIMojo::MainFrameObserver::DidFinishDocumentLoad() {
+  web_ui_mojo_->OnDidFinishDocumentLoad();
+}
+
 WebUIMojo::WebUIMojo(RenderView* render_view)
     : RenderViewObserver(render_view),
       RenderViewObserverTracker<WebUIMojo>(render_view),
-      main_frame_observer_(this) {
+      main_frame_observer_(this),
+      did_finish_document_load_(false) {
   CreateContextState();
 }
 
 void WebUIMojo::SetBrowserHandle(mojo::ScopedMessagePipeHandle handle) {
-  v8::HandleScope handle_scope(blink::mainThreadIsolate());
-  WebUIMojoContextState* state = GetContextState();
-  if (state)
-    state->SetHandle(handle.Pass());
+  if (did_finish_document_load_)
+    SetHandleOnContextState(handle.Pass());
+  else
+    pending_handle_ = handle.Pass();
 }
 
 WebUIMojo::~WebUIMojo() {
 }
 
 void WebUIMojo::CreateContextState() {
   v8::HandleScope handle_scope(blink::mainThreadIsolate());
   blink::WebFrame* frame = render_view()->GetWebView()->mainFrame();
   v8::Handle<v8::Context> context = frame->mainWorldScriptContext();
   gin::PerContextData* context_data = gin::PerContextData::From(context);
   WebUIMojoContextStateData* data = new WebUIMojoContextStateData;
   data->state.reset(new WebUIMojoContextState(
                         render_view()->GetWebView()->mainFrame(), context));
   context_data->SetUserData(kWebUIMojoContextStateKey, data);
 }
 
 void WebUIMojo::DestroyContextState(v8::Handle<v8::Context> context) {
   gin::PerContextData* context_data = gin::PerContextData::From(context);
   if (!context_data)
     return;
   context_data->RemoveUserData(kWebUIMojoContextStateKey);
 }
 
+void WebUIMojo::OnDidFinishDocumentLoad() {
+  did_finish_document_load_ = true;
+  if (pending_handle_.is_valid())
+    SetHandleOnContextState(pending_handle_.Pass());
+}
+
+void WebUIMojo::SetHandleOnContextState(mojo::ScopedMessagePipeHandle handle) {
+  DCHECK(did_finish_document_load_);
+  v8::HandleScope handle_scope(blink::mainThreadIsolate());
+  WebUIMojoContextState* state = GetContextState();
+  if (state)
+    state->SetHandle(handle.Pass());
+}
+
 WebUIMojoContextState* WebUIMojo::GetContextState() {
   blink::WebFrame* frame = render_view()->GetWebView()->mainFrame();
   v8::HandleScope handle_scope(blink::mainThreadIsolate());
   v8::Handle<v8::Context> context = frame->mainWorldScriptContext();
   gin::PerContextData* context_data = gin::PerContextData::From(context);
   if (!context_data)
     return NULL;
   WebUIMojoContextStateData* context_state =
       static_cast<WebUIMojoContextStateData*>(
           context_data->GetUserData(kWebUIMojoContextStateKey));
@@ skipping 14 matching lines @@
   WebUIMojoContextState* state = GetContextState();
   if (state && !state->module_added())
     return;
 
   v8::HandleScope handle_scope(blink::mainThreadIsolate());
   DestroyContextState(frame->mainWorldScriptContext());
   CreateContextState();
 }
 
 }  // namespace content