[Mac] Reduce jank in the cookie manager by lazily creating child nodes for the UI.

Also selects the first cookie node whene expanding an origin node.

BUG=33248
TEST=With a lot of cookies in your profile: Chromium-->Preferences-->Under the Hood-->Show cookies... Filter by a domain, expand the domain and the first cookie should be selected. Clear the filter and list should reappear speadily.

Review URL: http://codereview.chromium.org/554151

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@37695 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 23 insertions, 12 deletions

diff --git a/chrome/browser/cocoa/cookie_tree_node.h b/chrome/browser/cocoa/cookie_tree_node.h
index 5ff6695..1f161d5 100644
--- a/chrome/browser/cocoa/cookie_tree_node.h
+++ b/chrome/browser/cocoa/cookie_tree_node.h
@@ -12,6 +12,8 @@
 @interface CocoaCookieTreeNode : NSObject {
   scoped_nsobject<NSString> title_;
   scoped_nsobject<NSMutableArray> children_;
+  // We lazily create children, so we need to know if we are a leaf.
+  BOOL isLeaf_;
 
   // The platform-independent model node.
   CookieTreeNode* treeNode_;  // weak
@@ -39,7 +41,7 @@
 // Getters.
 - (NSString*)title;
 // |-children| is mutable so that the CookiesTreeModelObserverBridge can
-// operate on the children.
+// operate on the children. Note that this lazily creates children.
 - (NSMutableArray*)children;
 - (TreeModelNode*)treeNode;
 
diff --git a/chrome/browser/cocoa/cookie_tree_node.mm b/chrome/browser/cocoa/cookie_tree_node.mm
index 00ef5bc..53b7bab 100644
--- a/chrome/browser/cocoa/cookie_tree_node.mm
+++ b/chrome/browser/cocoa/cookie_tree_node.mm
@@ -15,15 +15,7 @@
   if ((self = [super init])) {
     DCHECK(node);
     treeNode_ = node;
-
-    const int childCount = node->GetChildCount();
-    children_.reset([[NSMutableArray alloc] initWithCapacity:childCount]);
-    for (int i = 0; i < childCount; ++i) {
-      CookieTreeNode* child = node->GetChild(i);
-      scoped_nsobject<CocoaCookieTreeNode> childNode(
-          [[CocoaCookieTreeNode alloc] initWithNode:child]);
-      [children_ addObject:childNode.get()];
-    }
+    isLeaf_ = (node->GetChildCount() == 0);
 
     [self rebuild];
   }
@@ -67,7 +59,7 @@
 }
 
 - (BOOL)isLeaf {
-  return ([children_ count] == 0);
+  return isLeaf_;
 }
 
 - (NSString*)title {
@@ -75,6 +67,16 @@
 }
 
 - (NSMutableArray*)children {
+  if (!children_.get()) {
+    const int childCount = treeNode_->GetChildCount();
+    children_.reset([[NSMutableArray alloc] initWithCapacity:childCount]);
+    for (int i = 0; i < childCount; ++i) {
+      CookieTreeNode* child = treeNode_->GetChild(i);
+      scoped_nsobject<CocoaCookieTreeNode> childNode(
+          [[CocoaCookieTreeNode alloc] initWithNode:child]);
+      [children_ addObject:childNode.get()];
+    }
+  }
   return children_.get();
 }
 
diff --git a/chrome/browser/cocoa/cookies_window_controller.mm b/chrome/browser/cocoa/cookies_window_controller.mm
index c997537..9ac09b7 100644
--- a/chrome/browser/cocoa/cookies_window_controller.mm
+++ b/chrome/browser/cocoa/cookies_window_controller.mm
@@ -306,6 +306,13 @@ bool CookiesTreeModelObserverBridge::HasCocoaModel() {
       children = [item childNodes];
       DCHECK_EQ([children count], 1U);
       [outlineView expandItem:[children lastObject]];
+      // Select the first node in that child set.
+      NSTreeNode* folderChild = [children lastObject];
+      if ([[folderChild childNodes] count] > 0) {
+        NSTreeNode* firstCookieChild =
+            [[folderChild childNodes] objectAtIndex:0];
+        [treeController_ setSelectionIndexPath:[firstCookieChild indexPath]];
+      }
     }
   }
 }
diff --git a/chrome/browser/cocoa/cookies_window_controller_unittest.mm b/chrome/browser/cocoa/cookies_window_controller_unittest.mm
index d3a729c..f1f9e1a 100644
--- a/chrome/browser/cocoa/cookies_window_controller_unittest.mm
+++ b/chrome/browser/cocoa/cookies_window_controller_unittest.mm
@@ -54,7 +54,7 @@
 @end
 @implementation CocoaCookieTreeNode (UglyHacks)
 - (NSMutableArray*)childs {
-  return children_.get();
+  return (NSMutableArray*)[self children];
 }
 @end