<webview> + <extensionview>: Generalize setValueIgnoreMutation

setValueIgnoreMutation should call setValue so that derived attribute objects
only need to modify setValue to get the desired behavior.

BUG=none
TBR=lazyboy@chromium.org

Review URL: https://codereview.chromium.org/928623002

Cr-Commit-Position: refs/heads/master@{#316318}

extensions/renderer/resources/guest_view/extension_view_attributes.js

@@ -37,7 +37,7 @@ ExtensionViewAttribute.prototype.setValue = function(value) {
 // Changes the attribute's value without triggering its mutation handler.
 ExtensionViewAttribute.prototype.setValueIgnoreMutation = function(value) {
   this.ignoreMutation = true;
-  this.extensionViewImpl.element.setAttribute(this.name, value || '');
+  this.setValue(value);
   this.ignoreMutation = false;
 }
 
@@ -80,9 +80,7 @@ SrcAttribute.prototype.__proto__ = ExtensionViewAttribute.prototype;
 
 SrcAttribute.prototype.setValueIgnoreMutation = function(value) {
   this.observer.takeRecords();
-  this.ignoreMutation = true;
-  this.extensionViewImpl.element.setAttribute(this.name, value || '');
-  this.ignoreMutation = false;
+  ExtensionViewAttribute.prototype.setValueIgnoreMutation.call(this, value);
 }
 
 SrcAttribute.prototype.handleMutation = function(oldValue, newValue) {

extensions/renderer/resources/guest_view/web_view_attributes.js

@@ -35,7 +35,7 @@ WebViewAttribute.prototype.setValue = function(value) {
 // Changes the attribute's value without triggering its mutation handler.
 WebViewAttribute.prototype.setValueIgnoreMutation = function(value) {
   this.ignoreMutation = true;
-  this.webViewImpl.element.setAttribute(this.name, value || '');
+  this.setValue(value);
   this.ignoreMutation = false;
 }
 
@@ -229,9 +229,7 @@ SrcAttribute.prototype.setValueIgnoreMutation = function(value) {
   // observer |observer|, and then get handled even though we do not want to
   // handle this mutation.
   this.observer.takeRecords();
-  this.ignoreMutation = true;
-  this.webViewImpl.element.setAttribute(this.name, value || '');
-  this.ignoreMutation = false;
+  WebViewAttribute.prototype.setValueIgnoreMutation.call(this, value);
 }
 
 SrcAttribute.prototype.handleMutation = function(oldValue, newValue) {