Serve mojo WebUI resources from the same origin as the WebUI itself.

content/renderer/web_ui_mojo_context_state.cc

Index: content/renderer/web_ui_mojo_context_state.cc
diff --git a/content/renderer/web_ui_mojo_context_state.cc b/content/renderer/web_ui_mojo_context_state.cc
index cb75e907e51eb1909b4554d47751f20fdf11a41e..b229cc983ad387d719b6c2f36d4044278ab80294 100644
--- a/content/renderer/web_ui_mojo_context_state.cc
+++ b/content/renderer/web_ui_mojo_context_state.cc
@@ -17,6 +17,7 @@
 #include "third_party/WebKit/public/platform/WebURLResponse.h"
 #include "third_party/WebKit/public/web/WebFrame.h"
 #include "third_party/WebKit/public/web/WebScriptSource.h"
+#include "third_party/WebKit/public/web/WebSecurityOrigin.h"
 
 using v8::Context;
 using v8::HandleScope;
@@ -29,10 +30,6 @@ namespace content {
 
 namespace {
 
-// All modules have this prefixed to them when downloading.
-// TODO(sky): move this into some common place.
-const char kModulePrefix[] = "chrome://mojo/";
-
 void RunMain(base::WeakPtr<gin::Runner> runner,
              v8::Local<v8::Value> module) {
   v8::Isolate* isolate = runner->GetContextHolder()->isolate();
@@ -48,7 +45,8 @@ void RunMain(base::WeakPtr<gin::Runner> runner,
 WebUIMojoContextState::WebUIMojoContextState(blink::WebFrame* frame,
                                              v8::Local<v8::Context> context)
     : frame_(frame),
-      module_added_(false) {
+      module_added_(false),
+      module_prefix_(frame_->securityOrigin().toString().utf8() + "/") {
   gin::PerContextData* context_data = gin::PerContextData::From(context);
   gin::ContextHolder* context_holder = context_data->context_holder();
   runner_.reset(new WebUIRunner(frame_, context_holder));
@@ -89,7 +87,7 @@ void WebUIMojoContextState::FetchModules(const std::vector<std::string>& ids) {
 }
 
 void WebUIMojoContextState::FetchModule(const std::string& id) {
-  const GURL url(kModulePrefix + id);
+  const GURL url(module_prefix_ + id);
   // TODO(sky): better error checks here?
   DCHECK(url.is_valid() && !url.is_empty());
   DCHECK(fetched_modules_.find(id) == fetched_modules_.end());
@@ -109,10 +107,10 @@ void WebUIMojoContextState::OnFetchModuleComplete(
     ResourceFetcher* fetcher,
     const blink::WebURLResponse& response,
     const std::string& data) {
-  DCHECK_EQ(kModulePrefix,
-      response.url().string().utf8().substr(0, arraysize(kModulePrefix) - 1));
+  DCHECK_EQ(module_prefix_,
+            response.url().string().utf8().substr(0, module_prefix_.size()));
   const std::string module =
-      response.url().string().utf8().substr(arraysize(kModulePrefix) - 1);
+      response.url().string().utf8().substr(module_prefix_.size());
   // We can't delete fetch right now as the arguments to this function come from
   // it and are used below. Instead use a scope_ptr to cleanup.
   scoped_ptr<ResourceFetcher> deleter(fetcher);