WebUI: Add JavaScript lifecycle-control to WebUIMessageHandler.

content/browser/webui/web_ui_impl.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 "content/browser/webui/web_ui_impl.h"
 
 #include <stddef.h>
 
 #include "base/debug/dump_without_crashing.h"
 #include "base/json/json_writer.h"
@@ skipping 126 matching lines @@
 }
 
 WebUIController* WebUIImpl::GetController() const {
   return controller_.get();
 }
 
 void WebUIImpl::SetController(WebUIController* controller) {
   controller_.reset(controller);
 }
 
+bool WebUIImpl::CanCallJavascript() {
+  RenderFrameHost* target_frame = TargetFrame();
+  return target_frame &&
+         (ChildProcessSecurityPolicyImpl::GetInstance()->HasWebUIBindings(
+              target_frame->GetProcess()->GetID()) ||
+          // It's possible to load about:blank in a Web UI renderer.
+          // See http://crbug.com/42547
+          target_frame->GetLastCommittedURL().spec() == url::kAboutBlankURL);
+}
+
 void WebUIImpl::CallJavascriptFunction(const std::string& function_name) {
   DCHECK(base::IsStringASCII(function_name));
   base::string16 javascript = base::ASCIIToUTF16(function_name + "();");
   ExecuteJavascript(javascript);
 }
 
 void WebUIImpl::CallJavascriptFunction(const std::string& function_name,
                                        const base::Value& arg) {
   DCHECK(base::IsStringASCII(function_name));
   std::vector<const base::Value*> args;
@@ skipping 69 matching lines @@
 // WebUIImpl, protected: -------------------------------------------------------
 
 void WebUIImpl::AddMessageHandler(WebUIMessageHandler* handler) {
   DCHECK(!handler->web_ui());
   handler->set_web_ui(this);
   handler->RegisterMessages();
   handlers_.push_back(handler);
 }
 
 void WebUIImpl::ExecuteJavascript(const base::string16& javascript) {
-  RenderFrameHost* target_frame = TargetFrame();
-  if (target_frame) {
-    if (!(ChildProcessSecurityPolicyImpl::GetInstance()->HasWebUIBindings(
-              target_frame->GetProcess()->GetID()) ||
-          // It's possible to load about:blank in a Web UI renderer.
-          // See http://crbug.com/42547
-          target_frame->GetLastCommittedURL().spec() == url::kAboutBlankURL)) {
-      // Silently ignore the request. Would be nice to clean-up WebUI so we
-      // could turn this into a CHECK(). http://crbug.com/516690.
-      return;
-    }
-    target_frame->ExecuteJavaScript(javascript);
-  }
+  // Silently ignore the request. Would be nice to clean-up WebUI so we
+  // could turn this into a CHECK(). http://crbug.com/516690.
+  if (!CanCallJavascript())
+    return;
+
+  TargetFrame()->ExecuteJavaScript(javascript);
 }
 
 RenderFrameHost* WebUIImpl::TargetFrame() {
   if (frame_name_.empty())
     return web_contents_->GetMainFrame();
 
   std::set<RenderFrameHost*> frame_set;
   web_contents_->ForEachFrame(base::Bind(&WebUIImpl::AddToSetIfFrameNameMatches,
                                          base::Unretained(this),
                                          &frame_set));
 
   // It happens that some sub-pages attempt to send JavaScript messages before
   // their frames are loaded.
   DCHECK_GE(1U, frame_set.size());
   if (frame_set.empty())
     return NULL;
   return *frame_set.begin();
 }
 
 void WebUIImpl::AddToSetIfFrameNameMatches(
     std::set<RenderFrameHost*>* frame_set,
     RenderFrameHost* host) {
   if (host->GetFrameName() == frame_name_)
     frame_set->insert(host);
 }
 
 }  // namespace content