Refactor renderer-side script injection

extensions/renderer/user_script_injection.cc

Index: extensions/renderer/user_script_injection.cc
diff --git a/extensions/renderer/user_script_injection.cc b/extensions/renderer/user_script_injection.cc
new file mode 100644
index 0000000000000000000000000000000000000000..0978deb2665219060b64667730e7e65a569c3e66
--- /dev/null
+++ b/extensions/renderer/user_script_injection.cc
@@ -0,0 +1,239 @@
+// 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 "extensions/renderer/user_script_injection.h"
+
+#include <vector>
+
+#include "base/lazy_instance.h"
+#include "base/metrics/histogram.h"
+#include "content/public/common/url_constants.h"
+#include "content/public/renderer/render_view.h"
+#include "extensions/common/extension.h"
+#include "extensions/common/extension_messages.h"
+#include "extensions/common/feature_switch.h"
+#include "extensions/common/permissions/permissions_data.h"
+#include "extensions/renderer/dom_activity_logger.h"
+#include "extensions/renderer/extension_groups.h"
+#include "grit/extensions_renderer_resources.h"
+#include "third_party/WebKit/public/web/WebDocument.h"
+#include "third_party/WebKit/public/web/WebFrame.h"
+#include "third_party/WebKit/public/web/WebScriptSource.h"
+#include "third_party/WebKit/public/web/WebView.h"
+#include "ui/base/resource/resource_bundle.h"
+#include "url/gurl.h"
+
+namespace extensions {
+
+namespace {
+
+const int kInvalidRequestId = -1;
+
+// The id of the next pending injection.
+int64 g_next_pending_id = 0;
+
+// These two strings are injected before and after the Greasemonkey API and
+// user script to wrap it in an anonymous scope.
+const char kUserScriptHead[] = "(function (unsafeWindow) {\n";
+const char kUserScriptTail[] = "\n})(window);";
+
+// Greasemonkey API source that is injected with the scripts.
+struct GreasemonkeyApiJsString {
+  GreasemonkeyApiJsString();
+  blink::WebScriptSource source;
+};
+
+// The below constructor, monstrous as it is, just makes a WebScriptSource from
+// the GreasemonkeyApiJs resource.
+GreasemonkeyApiJsString::GreasemonkeyApiJsString()
+    : source(blink::WebScriptSource(blink::WebString::fromUTF8(
+          ResourceBundle::GetSharedInstance()
+              .GetRawDataResource(IDR_GREASEMONKEY_API_JS)
+              .as_string()))) {
+}
+
+base::LazyInstance<GreasemonkeyApiJsString> g_greasemonkey_api =
+    LAZY_INSTANCE_INITIALIZER;
+
+}  // namespace
+
+UserScriptInjection::UserScriptInjection(
+    blink::WebFrame* web_frame,
+    const std::string& extension_id,
+    UserScript::RunLocation run_location,
+    int tab_id,
+    UserScriptSet* script_list,
+    const UserScript* script)
+    : ScriptInjection(web_frame,
+                      extension_id,
+                      run_location,
+                      tab_id),
+      script_(script),
+      script_id_(script_->id()),
+      user_script_set_observer_(this) {
+  user_script_set_observer_.Add(script_list);
+}
+
+UserScriptInjection::~UserScriptInjection() {
+}
+
+void UserScriptInjection::OnUserScriptsUpdated(
+    const std::set<std::string>& changed_extensions,
+    const std::vector<UserScript*>& scripts) {
+  // If the extension causing this injection changed, then this injection
+  // will be removed, and there's no guarantee the backing script still exists.
+  if (changed_extensions.count(extension_id()) > 0)
+    return;
+
+  for (std::vector<UserScript*>::const_iterator iter = scripts.begin();
+       iter != scripts.end();
+       ++iter) {
+    // We need to compare to |script_id_| (and not to script_->id()) because the
+    // old |script_| may be deleted by now.
+    if ((*iter)->id() == script_id_) {
+      script_ = *iter;
+      break;
+    }
+  }
+}
+
+bool UserScriptInjection::TryToInject(UserScript::RunLocation current_location,
+                                      const Extension* extension,
+                                      ScriptsRunInfo* scripts_run_info) {
+  // If the extension is removed, we return immediately and never inject.
+  if (!extension)
+    return true;
+
+  // If we are already waiting for permission, wait.
+  if (request_id() != -1)
+    return false;
+
+  // If the page is not to the proper load point, wait.
+  if (current_location < run_location())
+    return false;
+
+  // If we are not allowed to inject, then request permission and wait.
+  if (!Allowed(extension) && !RequestPermission(extension))
+    return false;
+
+  // Otherwise, we're good to inject!
+  Inject(extension, scripts_run_info);
+
+  return true;
+}
+
+bool UserScriptInjection::OnPermissionGranted(
+    const Extension* extension,
+    ScriptsRunInfo* scripts_run_info) {
+  if (!extension)
+    return false;
+
+  Inject(extension, scripts_run_info);
+  return true;
+}
+
+bool UserScriptInjection::Allowed(const Extension* extension) {
+  // If we don't have a tab id, we have no UI surface to ask for user consent.
+  // For now, we treat this as an automatic allow.
+  if (tab_id() == -1)
+    return true;
+
+  return !extension->permissions_data()->RequiresActionForScriptExecution(
+      extension, tab_id(), web_frame()->top()->document().url());
+}
+
+bool UserScriptInjection::RequestPermission(const Extension* extension) {
+  content::RenderView* render_view =
+      content::RenderView::FromWebView(web_frame()->top()->view());
+
+  // By default, we allow injection.
+  bool should_inject = true;
+  int64 request_id = kInvalidRequestId;
+  int page_id = render_view->GetPageId();
+
+  if (FeatureSwitch::scripts_require_action()->IsEnabled()) {
+    should_inject = false;
+    request_id = g_next_pending_id++;
+    set_request_id(request_id);
+  }
+
+  render_view->Send(new ExtensionHostMsg_RequestScriptInjectionPermission(
+      render_view->GetRoutingID(), extension->id(), page_id, request_id));
+
+  return should_inject;
+}
+
+void UserScriptInjection::Inject(const Extension* extension,
+                                 ScriptsRunInfo* scripts_run_info) {
+  if (!script_->css_scripts().empty() &&
+      run_location() == UserScript::DOCUMENT_START) {
+    InjectCSS(scripts_run_info);
+  }
+  if (!script_->js_scripts().empty() &&
+      script_->run_location() == run_location()) {
+    InjectJS(extension, scripts_run_info);
+  }
+}
+
+void UserScriptInjection::InjectJS(const Extension* extension,
+                                   ScriptsRunInfo* scripts_run_info) {
+  const UserScript::FileList& js_scripts = script_->js_scripts();
+  std::vector<blink::WebScriptSource> sources;
+  scripts_run_info->num_js += js_scripts.size();
+
+  bool is_standalone_or_emulate_greasemonkey =
+      script_->is_standalone() || script_->emulate_greasemonkey();
+  for (UserScript::FileList::const_iterator iter = js_scripts.begin();
+       iter != js_scripts.end();
+       ++iter) {
+    std::string content = iter->GetContent().as_string();
+
+    // We add this dumb function wrapper for standalone user script to
+    // emulate what Greasemonkey does.
+    // TODO(aa): I think that maybe "is_standalone" scripts don't exist
+    // anymore. Investigate.
+    if (is_standalone_or_emulate_greasemonkey) {
+      content.insert(0, kUserScriptHead);
+      content += kUserScriptTail;
+    }
+    sources.push_back(blink::WebScriptSource(
+        blink::WebString::fromUTF8(content), iter->url()));
+  }
+
+  // Emulate Greasemonkey API for scripts that were converted to extensions
+  // and "standalone" user scripts.
+  if (is_standalone_or_emulate_greasemonkey)
+    sources.insert(sources.begin(), g_greasemonkey_api.Get().source);
+
+  int isolated_world_id =
+      GetIsolatedWorldIdForExtension(extension, web_frame());
+  base::ElapsedTimer exec_timer;
+  DOMActivityLogger::AttachToWorld(isolated_world_id, script_->extension_id());
+  web_frame()->executeScriptInIsolatedWorld(isolated_world_id,
+                                            &sources.front(),
+                                            sources.size(),
+                                            EXTENSION_GROUP_CONTENT_SCRIPTS);
+  UMA_HISTOGRAM_TIMES("Extensions.InjectScriptTime", exec_timer.Elapsed());
+
+  for (std::vector<blink::WebScriptSource>::const_iterator iter =
+           sources.begin();
+       iter != sources.end();
+       ++iter) {
+    scripts_run_info->executing_scripts[script_->extension_id()].insert(
+        GURL(iter->url).path());
+  }
+}
+
+void UserScriptInjection::InjectCSS(ScriptsRunInfo* scripts_run_info) {
+  const UserScript::FileList& css_scripts = script_->css_scripts();
+  scripts_run_info->num_css += css_scripts.size();
+  for (UserScript::FileList::const_iterator iter = css_scripts.begin();
+       iter != css_scripts.end();
+       ++iter) {
+    web_frame()->document().insertStyleSheet(
+        blink::WebString::fromUTF8(iter->GetContent().as_string()));
+  }
+}
+
+}  // namespace extensions