Introduce ScriptInjection in extensions/renderer to inject UserScripts

extensions/renderer/script_injection.cc

Index: extensions/renderer/script_injection.cc
diff --git a/extensions/renderer/script_injection.cc b/extensions/renderer/script_injection.cc
new file mode 100644
index 0000000000000000000000000000000000000000..4db534a1f68c1934127ec61a5617c701d28aa40b
--- /dev/null
+++ b/extensions/renderer/script_injection.cc
@@ -0,0 +1,202 @@
+// 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/script_injection.h"
+
+#include <vector>
+
+#include "base/lazy_instance.h"
+#include "base/metrics/histogram.h"
+#include "content/public/common/url_constants.h"
+#include "extensions/common/extension.h"
+#include "extensions/common/extension_messages.h"
+#include "extensions/common/permissions/permissions_data.h"
+#include "extensions/renderer/dom_activity_logger.h"
+#include "extensions/renderer/extension_groups.h"
+#include "extensions/renderer/script_context.h"
+#include "extensions/renderer/user_script_slave.h"
+#include "grit/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 "ui/base/resource/resource_bundle.h"
+#include "url/gurl.h"
+
+namespace extensions {
+
+namespace {
+
+// 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
+
+ScriptInjection::ScriptsRunInfo::ScriptsRunInfo() : num_css(0u), num_js(0u) {
+}
+
+ScriptInjection::ScriptsRunInfo::~ScriptsRunInfo() {
+}
+
+// static
+GURL ScriptInjection::GetDocumentUrlForFrame(blink::WebFrame* frame) {
+  GURL data_source_url = ScriptContext::GetDataSourceURLForFrame(frame);
+  if (!data_source_url.is_empty() && frame->isViewSourceModeEnabled()) {
+    data_source_url = GURL(content::kViewSourceScheme + std::string(":") +
+                           data_source_url.spec());
+  }
+
+  return data_source_url;
+}
+
+ScriptInjection::ScriptInjection(
+    scoped_ptr<UserScript> script,
+    UserScriptSlave* user_script_slave)
+    : script_(script.Pass()),
+      extension_id_(script_->extension_id()),
+      user_script_slave_(user_script_slave),
+      is_standalone_or_emulate_greasemonkey_(
+          script_->is_standalone() || script_->emulate_greasemonkey()) {
+}
+
+ScriptInjection::~ScriptInjection() {
+}
+
+bool ScriptInjection::WantsToRun(blink::WebFrame* frame,
+                                 UserScript::RunLocation run_location,
+                                 const GURL& document_url) const {
+  if (frame->parent() && !script_->match_all_frames())
+    return false;  // Only match subframes if the script declared it wanted to.
+
+  const Extension* extension = user_script_slave_->GetExtension(extension_id_);
+  // Since extension info is sent separately from user script info, they can
+  // be out of sync. We just ignore this situation.
+  if (!extension)
+    return false;
+
+  // Content scripts are not tab-specific.
+  static const int kNoTabId = -1;
+  // We don't have a process id in this context.
+  static const int kNoProcessId = -1;
+
+  GURL effective_document_url = ScriptContext::GetEffectiveDocumentURL(
+      frame, document_url, script_->match_about_blank());
+
+  if (!PermissionsData::CanExecuteScriptOnPage(extension,
+                                               effective_document_url,
+                                               frame->top()->document().url(),
+                                               kNoTabId,
+                                               script_.get(),
+                                               kNoProcessId,
+                                               NULL /* ignore error */)) {
+    return false;
+  }
+
+  return ShouldInjectCSS(run_location) || ShouldInjectJS(run_location);
+}
+
+void ScriptInjection::Inject(blink::WebFrame* frame,
+                             UserScript::RunLocation run_location,
+                             ScriptsRunInfo* scripts_run_info) const {
+  DCHECK(frame);
+  DCHECK(scripts_run_info);
+  DCHECK(WantsToRun(frame, run_location, GetDocumentUrlForFrame(frame)));
+  DCHECK(user_script_slave_->GetExtension(extension_id_));
+
+  if (ShouldInjectCSS(run_location))
+    InjectCSS(frame, scripts_run_info);
+  if (ShouldInjectJS(run_location))
+    InjectJS(frame, scripts_run_info);
+}
+
+bool ScriptInjection::ShouldInjectJS(UserScript::RunLocation run_location)
+    const {
+  return !script_->js_scripts().empty() &&
+         script_->run_location() == run_location;
+}
+
+bool ScriptInjection::ShouldInjectCSS(UserScript::RunLocation run_location)
+    const {
+  return !script_->css_scripts().empty() &&
+         run_location == UserScript::DOCUMENT_START;
+}
+
+void ScriptInjection::InjectJS(blink::WebFrame* frame,
+                               ScriptsRunInfo* scripts_run_info) const {
+  const UserScript::FileList& js_scripts = script_->js_scripts();
+  std::vector<blink::WebScriptSource> sources;
+  scripts_run_info->num_js += js_scripts.size();
+  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 =
+      user_script_slave_->GetIsolatedWorldIdForExtension(
+          user_script_slave_->GetExtension(extension_id_), frame);
+  base::ElapsedTimer exec_timer;
+  DOMActivityLogger::AttachToWorld(isolated_world_id, extension_id_);
+  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[extension_id_].insert(
+        GURL(iter->url).path());
+  }
+}
+
+void ScriptInjection::InjectCSS(blink::WebFrame* frame,
+                                ScriptsRunInfo* scripts_run_info) const {
+  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) {
+    frame->document().insertStyleSheet(
+        blink::WebString::fromUTF8(iter->GetContent().as_string()));
+  }
+}
+
+}  // namespace extensions