<webview> + <extensionview>: Create a maybeHandleMutation call into attributes

web_view.js and extension_view.js call into maybeHandleMutation which will call
handleMutation if the mutation is not set to be ignored. This removes access to
the ignoreMutation field outside of attribute objects.

This CL also fixes a bug in extensionview src attribute where it does not access
the ignoreMutation field properly.

BUG=none
TBR=lazyboy@chromium.org

Review URL: https://codereview.chromium.org/929453002

Cr-Commit-Position: refs/heads/master@{#316273}

extensions/renderer/resources/guest_view/extension_view.js

@@ -52,7 +52,7 @@ ExtensionViewImpl.prototype.handleAttributeMutation = function(
     return;
 
   // Let the changed attribute handle its own mutation;
-  this.attributes[attributeName].handleMutation(oldValue, newValue);
+  this.attributes[attributeName].maybeHandleMutation(oldValue, newValue);
 };
 
 ExtensionViewImpl.prototype.onElementDetached = function() {
@@ -63,4 +63,4 @@ ExtensionViewImpl.prototype.onElementDetached = function() {
 GuestViewContainer.registerElement(ExtensionViewImpl);
 
 // Exports.
-exports.ExtensionViewImpl = ExtensionViewImpl;
+exports.ExtensionViewImpl = ExtensionViewImpl;
\ No newline at end of file

extensions/renderer/resources/guest_view/extension_view_attributes.js

@@ -55,6 +55,16 @@ ExtensionViewAttribute.prototype.defineProperty = function() {
 };
 
 // Called when the attribute's value changes.
+ExtensionViewAttribute.prototype.maybeHandleMutation =
+    function(oldValue, newValue) {
+  if (this.ignoreMutation) {
+    return;
+  }
+
+  this.handleMutation(oldValue, newValue);
+}
+
+// Called when a change that isn't ignored occurs to the attribute's value.
 ExtensionViewAttribute.prototype.handleMutation =
     function(oldValue, newValue) {};
 
@@ -76,9 +86,6 @@ SrcAttribute.prototype.setValueIgnoreMutation = function(value) {
 }
 
 SrcAttribute.prototype.handleMutation = function(oldValue, newValue) {
-  if (this.attributes[attributeName].ignoreMutation)
-    return;
-
   if (!newValue && oldValue) {
     this.setValueIgnoreMutation(oldValue);
     return;

extensions/renderer/resources/guest_view/web_view.js

@@ -107,13 +107,12 @@ WebViewImpl.prototype.setupElementProperties = function() {
 // This observer monitors mutations to attributes of the <webview>.
 WebViewImpl.prototype.handleAttributeMutation = function(
     attributeName, oldValue, newValue) {
-  if (!this.attributes[attributeName] ||
-      this.attributes[attributeName].ignoreMutation) {
+  if (!this.attributes[attributeName]) {
     return;
   }
 
   // Let the changed attribute handle its own mutation;
-  this.attributes[attributeName].handleMutation(oldValue, newValue);
+  this.attributes[attributeName].maybeHandleMutation(oldValue, newValue);
 };
 
 WebViewImpl.prototype.onSizeChanged = function(webViewEvent) {

extensions/renderer/resources/guest_view/web_view_attributes.js

@@ -53,6 +53,15 @@ WebViewAttribute.prototype.defineProperty = function() {
 };
 
 // Called when the attribute's value changes.
+WebViewAttribute.prototype.maybeHandleMutation = function(oldValue, newValue) {
+  if (this.ignoreMutation) {
+    return;
+  }
+
+  this.handleMutation(oldValue, newValue);
+};
+
+// Called when a change that isn't ignored occurs to the attribute's value.
 WebViewAttribute.prototype.handleMutation = function(oldValue, newValue) {};
 
 // An attribute that is treated as a Boolean.