[Extensions] Use OnceCallback in ScriptExecutor::ExecuteScript

ScriptFinishedCallback can/should be a OnceCallback as
it would only run (at most) once. This makes internal class Handler
take OnceCallbacks too, simplifying the code a bit.

Bug: None
Change-Id: Id74e83ba255c9507ea778a7ad9fef08f8d7b9dbd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2133659
Commit-Queue: Istiaque Ahmed <lazyboy@chromium.org>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#760318}

extensions/browser/script_executor.cc

@@ -51,12 +51,16 @@ const std::string GenerateInjectionKey(const HostID& host_id,
 // corresponding response comes from the renderer, or the renderer is destroyed.
 class Handler : public content::WebContentsObserver {
  public:
-  Handler(ScriptsExecutedNotification observer,
+  // OnceCallback version of ScriptExecutor::ScriptsExecutedNotification:
+  using ScriptsExecutedOnceCallback = base::OnceCallback<
+      void(content::WebContents*, const ExecutingScriptsMap&, const GURL&)>;
+
+  Handler(ScriptsExecutedOnceCallback observer,
           content::WebContents* web_contents,
           const ExtensionMsg_ExecuteCode_Params& params,
           ScriptExecutor::FrameScope scope,
           int frame_id,
-          const ScriptExecutor::ScriptFinishedCallback& callback)
+          ScriptExecutor::ScriptFinishedCallback callback)
       : content::WebContentsObserver(web_contents),
         observer_(std::move(observer)),
         host_id_(params.host_id),
@@ -65,7 +69,7 @@ class Handler : public content::WebContentsObserver {
         root_rfh_(ExtensionApiFrameIdMap::GetRenderFrameHostById(web_contents,
                                                                  frame_id)),
         root_is_main_frame_(root_rfh_ ? !root_rfh_->GetParent() : false),
-        callback_(callback) {
+        callback_(std::move(callback)) {
     if (root_rfh_) {
       if (include_sub_frames_) {
         web_contents->ForEachFrame(base::BindRepeating(
@@ -180,17 +184,18 @@ class Handler : public content::WebContentsObserver {
       results_.Clear();
     }
 
-    if (!observer_.is_null() && root_frame_error_.empty() &&
+    if (observer_ && root_frame_error_.empty() &&
         host_id_.type() == HostID::EXTENSIONS) {
-      observer_.Run(web_contents(), {{host_id_.id(), {}}}, root_frame_url_);
+      std::move(observer_).Run(web_contents(), {{host_id_.id(), {}}},
+                               root_frame_url_);
     }
 
-    if (!callback_.is_null())
-      callback_.Run(root_frame_error_, root_frame_url_, results_);
+    if (callback_)
+      std::move(callback_).Run(root_frame_error_, root_frame_url_, results_);
     delete this;
   }
 
-  ScriptsExecutedNotification observer_;
+  ScriptsExecutedOnceCallback observer_;
 
   // The id of the host (the extension or the webui) doing the injection.
   HostID host_id_;
@@ -248,7 +253,7 @@ void ScriptExecutor::ExecuteScript(const HostID& host_id,
                                    bool user_gesture,
                                    base::Optional<CSSOrigin> css_origin,
                                    ScriptExecutor::ResultType result_type,
-                                   const ScriptFinishedCallback& callback) {
+                                   ScriptFinishedCallback callback) {
   if (host_id.type() == HostID::EXTENSIONS) {
     // Don't execute if the extension has been unloaded.
     const Extension* extension =
@@ -281,7 +286,7 @@ void ScriptExecutor::ExecuteScript(const HostID& host_id,
 
   // Handler handles IPCs and deletes itself on completion.
   new Handler(observer_, web_contents_, params, frame_scope, frame_id,
-              callback);
+              std::move(callback));
 }
 
 }  // namespace extensions

extensions/browser/script_executor.h

@@ -79,9 +79,8 @@ class ScriptExecutor {
 
   // Callback from ExecuteScript. The arguments are (error, on_url, result).
   // Success is implied by an empty error.
-  typedef base::Callback<
-      void(const std::string&, const GURL&, const base::ListValue&)>
-      ScriptFinishedCallback;
+  using ScriptFinishedCallback = base::OnceCallback<
+      void(const std::string&, const GURL&, const base::ListValue&)>;
 
   // Executes a script. The arguments match ExtensionMsg_ExecuteCode_Params in
   // extension_messages.h (request_id is populated automatically).
@@ -106,7 +105,7 @@ class ScriptExecutor {
                      bool user_gesture,
                      base::Optional<CSSOrigin> css_origin,
                      ResultType result_type,
-                     const ScriptFinishedCallback& callback);
+                     ScriptFinishedCallback callback);
 
   // Set the observer for ScriptsExecutedNotification callbacks.
   void set_observer(ScriptsExecutedNotification observer) {