Extract executeScript-like functionality into a single ExtensionScriptExecutor class.

chrome/browser/extensions/script_executor_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 "chrome/browser/extensions/script_executor_impl.h"
+
+#include "base/callback.h"
+#include "base/logging.h"
+#include "base/pickle.h"
+#include "chrome/common/extensions/extension_messages.h"
+#include "content/public/browser/render_view_host.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_observer.h"
+#include "ipc/ipc_message.h"
+#include "ipc/ipc_message_macros.h"
+
+namespace extensions {
+
+namespace {
+
+const char* kRendererDestroyed = "Renderer destroyed";

[Matt Perry, 2012/05/11 22:47:38]

maybe "The tab was closed." would be more human readable.

[not at google - send to devlin, 2012/05/14 02:27:16]

Done.

+
+class Handler : public content::WebContentsObserver {

[koz (OOO until 15th September), 2012/05/11 01:09:16]

Could you please add a comment here explaining the lifetime of this class?

[not at google - send to devlin, 2012/05/14 02:27:16]

Done.

+ public:
+  Handler(content::WebContents* web_contents,
+          const ExtensionMsg_ExecuteCode_Params params,
+          const ScriptExecutor::ExecuteScriptCallback& callback)
+          : request_id_(params.request_id),
+            callback_(callback) {
+    content::RenderViewHost* rvh = web_contents->GetRenderViewHost();
+    rvh->Send(new ExtensionMsg_ExecuteCode(rvh->GetRoutingID(), params));
+    Observe(web_contents);

[koz (OOO until 15th September), 2012/05/11 01:09:16]

Maybe a comment like

"Wait for WebContentsDestroyed() where we delete ourselves."

[not at google - send to devlin, 2012/05/14 02:27:16]

It would be OnMessageReceived too, but yeah, realised I can just do this
automatically in the constructor/destructor by calling the WebContentsObserver
constructor properly.

+  }
+
+  virtual ~Handler() {}
+
+  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE {
+    // Unpack by hand to check the request_id, since there may be multiple
+    // requests in flight but only one is for this.
+    if (message.type() != ExtensionHostMsg_ExecuteCodeFinished::ID)
+      return false;
+
+    int message_request_id;
+    PickleIterator iter(message);
+    CHECK(message.ReadInt(&iter, &message_request_id));
+
+    if (message_request_id != request_id_)
+      return false;
+
+    IPC_BEGIN_MESSAGE_MAP(Handler, message)
+      IPC_MESSAGE_HANDLER(ExtensionHostMsg_ExecuteCodeFinished,
+                          OnExecuteCodeFinished)
+    IPC_END_MESSAGE_MAP()
+    return true;
+  }
+
+  virtual void WebContentsDestroyed(content::WebContents* tab) OVERRIDE {
+    Observe(NULL);
+    callback_.Run(false, kRendererDestroyed);
+    delete this;
+  }
+
+ private:
+  void OnExecuteCodeFinished(int request_id,
+                             bool success,
+                             const std::string& error) {
+    Observe(NULL);
+    callback_.Run(success, error);
+    delete this;
+  }
+
+  int request_id_;
+  ScriptExecutor::ExecuteScriptCallback callback_;
+};
+
+}  // namespace
+
+ScriptExecutorImpl::ScriptExecutorImpl(
+    content::WebContents* web_contents)
+    : next_request_id_(0),
+      web_contents_(web_contents) {}
+
+ScriptExecutorImpl::~ScriptExecutorImpl() {}
+
+void ScriptExecutorImpl::ExecuteScript(
+    const std::string& extension_id,
+    bool is_javascript,
+    const std::string& code,
+    bool all_frames,
+    UserScript::RunLocation run_at,
+    bool in_main_world,
+    const ExecuteScriptCallback& callback) {
+  ExtensionMsg_ExecuteCode_Params params;
+  params.request_id = next_request_id_++;
+  params.extension_id = extension_id;
+  params.is_javascript = is_javascript;
+  params.code = code;
+  params.all_frames = all_frames;
+  params.run_at = (int) run_at;
+  params.in_main_world = in_main_world;
+
+  // Handler handles IPCs and deletes itself on completion.
+  new Handler(web_contents_, params, callback);
+}
+
+}  // namespace extensions