[Extensions] Use fetch/createImageBitmap in loadImagePath.

This change uses code that is compatible with both Service Worker-based
extensions and background/event page-based extensions to implement the
browserAction.setIcon() JavaScript code.

Bug: 1015136
Change-Id: I1bc55cd5da2cc106e8d74dba172122d2bf943d31
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1921640Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Commit-Queue: David Bertoni <dbertoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#718928}

extensions/renderer/module_system.cc

@@ -658,7 +658,7 @@ v8::Local<v8::String> ModuleSystem::WrapSource(v8::Local<v8::String> source) {
       GetIsolate(),
       "(function(require, requireNative, loadScript, exports, console, "
       "privates, apiBridge, bindingUtil, getInternalApi, $Array, $Function, "
-      "$JSON, $Object, $RegExp, $String, $Error) {"
+      "$JSON, $Object, $RegExp, $String, $Error, $Promise) {"
       "'use strict';");
   v8::Local<v8::String> right = ToV8StringUnsafe(GetIsolate(), "\n})");
   return handle_scope.Escape(v8::Local<v8::String>(v8::String::Concat(
@@ -798,6 +798,7 @@ v8::Local<v8::Value> ModuleSystem::LoadModuleWithNativeAPIBridge(
       context_->safe_builtins()->GetRegExp(),
       context_->safe_builtins()->GetString(),
       context_->safe_builtins()->GetError(),
+      context_->safe_builtins()->GetPromise(),
   };
   {
     v8::TryCatch try_catch(GetIsolate());

extensions/renderer/resources/set_icon.js

@@ -5,23 +5,32 @@
 var SetIconCommon = requireNative('setIcon').SetIconCommon;
 
 function loadImagePath(path, callback) {
-  var img = new Image();
-  img.onerror = function() {
-    console.error('Could not load action icon \'' + path + '\'.');
-  };
-  img.onload = function() {
-    var canvas = document.createElement('canvas');
-    canvas.width = img.width;
-    canvas.height = img.height;
+  let fetchPromise = fetch(path);
 
+  let blobPromise = $Promise.then(fetchPromise, function(response) {
+    if (!response.ok) {
+      throw new $Error.self('Could not load action icon \'' + path + '\'.');
+    }
+    return response.blob();
+  });
+
+  let imagePromise = $Promise.then(blobPromise, function(blob) {
+    return createImageBitmap(blob);
+  });
+
+  let imageDataPromise = $Promise.then(imagePromise, function(image) {
+    var canvas = new OffscreenCanvas(image.width, image.height);
     var canvas_context = canvas.getContext('2d');
     canvas_context.clearRect(0, 0, canvas.width, canvas.height);
-    canvas_context.drawImage(img, 0, 0, canvas.width, canvas.height);
+    canvas_context.drawImage(image, 0, 0, canvas.width, canvas.height);
     var imageData = canvas_context.getImageData(0, 0, canvas.width,
                                                 canvas.height);
     callback(imageData);
-  };
-  img.src = path;
+  });
+
+  $Promise.catch(imageDataPromise, function(error) {
+    console.error(error);
+  });
 }
 
 function smellsLikeImageData(imageData) {

extensions/renderer/safe_builtins.cc

@@ -87,6 +87,8 @@ const char kScript[] =
     "saveBuiltin(Error,\n"
     "            [],\n"
     "            ['captureStackTrace']);\n"
+    "saveBuiltin(Promise,\n"
+    "            ['then', 'catch']);\n"
     "\n"
     "// JSON is trickier because extensions can override toJSON in\n"
     "// incompatible ways, and we need to prevent that.\n"
@@ -258,4 +260,8 @@ v8::Local<v8::Object> SafeBuiltins::GetError() const {
   return Load("Error", context_->v8_context());
 }
 
+v8::Local<v8::Object> SafeBuiltins::GetPromise() const {
+  return Load("Promise", context_->v8_context());
+}
+
 }  //  namespace extensions

extensions/renderer/safe_builtins.h

@@ -39,6 +39,7 @@ class SafeBuiltins {
   v8::Local<v8::Object> GetRegExp() const;
   v8::Local<v8::Object> GetString() const;
   v8::Local<v8::Object> GetError() const;
+  v8::Local<v8::Object> GetPromise() const;
 
  private:
   ScriptContext* context_;