From 11b49930f9837e7b461d5d49201b0c68aa6e02af Mon Sep 17 00:00:00 2001
From: Sean Lip <sll@google.com>
Date: Thu, 9 Jun 2016 19:10:34 -0700
Subject: [PATCH] Remove the unnecessary construction of new services.

---
 accessible/appview.component.js            |  6 +++---
 accessible/clipboard.service.js            |  1 +
 accessible/fieldview.component.js          |  3 +--
 accessible/toolbox_treeview.component.js   | 11 ++++++-----
 accessible/tree.service.js                 |  2 ++
 accessible/utils.service.js                |  7 +++++--
 accessible/workspace_treeview.component.js |  7 ++++---
 7 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/accessible/appview.component.js b/accessible/appview.component.js
index 792726654..6a3cc87bd 100644
--- a/accessible/appview.component.js
+++ b/accessible/appview.component.js
@@ -55,10 +55,10 @@ blocklyApp.AppView = ng.core
     `,
     directives: [blocklyApp.ToolboxView, blocklyApp.WorkspaceView],
     pipes: [blocklyApp.TranslatePipe],
-    // ClipboardService declared here so that all components are using the same
-    // instance of the clipboard.
+    // The clipboard and utils services are declared here, so that all
+    // components in the application use the same instance of the service.
     // https://www.sitepoint.com/angular-2-components-providers-classes-factories-values/
-    providers: [blocklyApp.ClipboardService]
+    providers: [blocklyApp.ClipboardService, blocklyApp.UtilsService]
   })
   .Class({
     constructor: function() {}
diff --git a/accessible/clipboard.service.js b/accessible/clipboard.service.js
index 747baf0e2..25508fc6c 100644
--- a/accessible/clipboard.service.js
+++ b/accessible/clipboard.service.js
@@ -25,6 +25,7 @@
 blocklyApp.ClipboardService = ng.core
   .Class({
     constructor: function() {
+      blocklyApp.debug && console.log('Clipboard service constructed');
       this.clipboardBlockXml_ = null;
       this.clipboardBlockSuperiorConnection_ = null;
       this.clipboardBlockNextConnection_ = null;
diff --git a/accessible/fieldview.component.js b/accessible/fieldview.component.js
index cdd52e117..114a256b6 100644
--- a/accessible/fieldview.component.js
+++ b/accessible/fieldview.component.js
@@ -62,8 +62,7 @@ blocklyApp.FieldView = ng.core
     </li>
     `,
     inputs: ['field', 'level', 'index', 'parentId'],
-    pipes: [blocklyApp.TranslatePipe],
-    providers: [blocklyApp.TreeService, blocklyApp.UtilsService]
+    pipes: [blocklyApp.TranslatePipe]
   })
   .Class({
     constructor: [blocklyApp.UtilsService, function(_utilsService) {
diff --git a/accessible/toolbox_treeview.component.js b/accessible/toolbox_treeview.component.js
index 1e50ca196..0411c3fba 100644
--- a/accessible/toolbox_treeview.component.js
+++ b/accessible/toolbox_treeview.component.js
@@ -105,13 +105,14 @@ blocklyApp.ToolboxTreeView = ng.core
     }), blocklyApp.FieldView],
     inputs: [
         'block', 'displayBlockMenu', 'level', 'index', 'tree', 'noCategories'],
-    pipes: [blocklyApp.TranslatePipe],
-    providers: [blocklyApp.TreeService, blocklyApp.UtilsService]
+    pipes: [blocklyApp.TranslatePipe]
   })
   .Class({
-    constructor: [blocklyApp.ClipboardService, blocklyApp.TreeService,
-                  blocklyApp.UtilsService,
-                  function(_clipboardService, _treeService, _utilsService) {
+    constructor: [
+        blocklyApp.ClipboardService, blocklyApp.TreeService, blocklyApp.UtilsService,
+        function(_clipboardService, _treeService, _utilsService) {
+      // ClipboardService and UtilsService are app-wide singleton services.
+      // TreeService is from the parent ToolboxView component.
       this.infoBlocks = Object.create(null);
       this.clipboardService = _clipboardService;
       this.treeService = _treeService;
diff --git a/accessible/tree.service.js b/accessible/tree.service.js
index 549df25db..6682f66af 100644
--- a/accessible/tree.service.js
+++ b/accessible/tree.service.js
@@ -19,6 +19,8 @@
 
 /**
  * @fileoverview Angular2 Service that handles all tree keyboard navigation.
+ * A separate TreeService is constructed for each tree in the application.
+ *
  * @author madeeha@google.com (Madeeha Ghori)
  */
 
diff --git a/accessible/utils.service.js b/accessible/utils.service.js
index fddb47ded..569dc7aa1 100644
--- a/accessible/utils.service.js
+++ b/accessible/utils.service.js
@@ -18,8 +18,10 @@
  */
 
 /**
- * @fileoverview Angular2 Service with functions required by multiple
- * components.
+ * @fileoverview Angular2 utility service for multiple components. All
+ * functions in this service should be stateless, since this is a singleton
+ * service that is used for the entire application.
+ *
  * @author madeeha@google.com (Madeeha Ghori)
  */
 
@@ -28,6 +30,7 @@ var blocklyApp = {};
 blocklyApp.UtilsService = ng.core
   .Class({
     constructor: function() {
+      blocklyApp.debug && console.log('Utils service constructed');
     },
     generateUniqueId: function() {
       return 'blockly-' + Blockly.genUid();
diff --git a/accessible/workspace_treeview.component.js b/accessible/workspace_treeview.component.js
index e6f492cdb..3740e4dec 100644
--- a/accessible/workspace_treeview.component.js
+++ b/accessible/workspace_treeview.component.js
@@ -117,11 +117,12 @@ blocklyApp.WorkspaceTreeView = ng.core
                [level]="level">
     </tree-view>
     `,
-    directives: [ng.core.forwardRef(
-        function() { return blocklyApp.WorkspaceTreeView; }), blocklyApp.FieldView],
+    directives: [ng.core.forwardRef(function() {
+      return blocklyApp.WorkspaceTreeView;
+    }), blocklyApp.FieldView],
     inputs: ['block', 'isTopBlock', 'topBlockIndex', 'level', 'parentId'],
     pipes: [blocklyApp.TranslatePipe],
-    providers: [blocklyApp.TreeService, blocklyApp.UtilsService],
+    providers: [blocklyApp.TreeService],
   })
   .Class({
     constructor: [