Fix a leak in Touch Bar text suggestions.

Each leaked NSCandidateListTouchBarItem carried a CALayer and other
resources; holding on to them caused a major slowdown.

This change makes |-createCandidateListItem| return an autoreleased
NSCandidateListTouchBarItem instead of a retained one, and renames it to
|-makeCandidateListItem| to match the naming and ownership semantics of
|-makeTouchBar| (and be consistent with the create rule).

Bug: 877137
Change-Id: Icfb335c341cb86e8691562ade4c222a59c990bf7
Reviewed-on: https://chromium-review.googlesource.com/1208428Reviewed-by: Sarah Chan <spqchan@chromium.org>
Commit-Queue: Sidney San Martín <sdy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589195}

chrome/browser/ui/cocoa/touchbar/text_suggestions_touch_bar_controller.h

@@ -37,7 +37,7 @@ class Range;
 
 // Creates a NSCandidateListTouchBarItem that contains text suggestions
 // based on the current text selection.
-- (NSCandidateListTouchBarItem*)createCandidateListItem
+- (NSCandidateListTouchBarItem*)makeCandidateListItem
     API_AVAILABLE(macos(10.12.2));
 
 - (void)candidateListTouchBarItem:(NSCandidateListTouchBarItem*)anItem
@@ -77,4 +77,4 @@ class Range;
 
 @end
 
-#endif  // CHROME_BROWSER_UI_COCOA_TOUCHBAR_SUGGESTED_TEXT_TOUCH_BAR_CONTROLLER_H_
+#endif  // CHROME_BROWSER_UI_COCOA_TOUCHBAR_SUGGESTED_TEXT_TOUCH_BAR_CONTROLLER_H_
\ No newline at end of file

chrome/browser/ui/cocoa/touchbar/text_suggestions_touch_bar_controller.mm

@@ -126,23 +126,23 @@ class WebContentsTextObserver : public content::WebContentsObserver {
   if (![identifier hasSuffix:kTextSuggestionsItemsTouchId])
     return nil;
 
-  return [self createCandidateListItem];
+  return [self makeCandidateListItem];
 }
 
-- (NSCandidateListTouchBarItem*)createCandidateListItem {
-  NSCandidateListTouchBarItem* candidateListItem =
+- (NSCandidateListTouchBarItem*)makeCandidateListItem {
+  base::scoped_nsobject<NSCandidateListTouchBarItem> candidateListItem(
       [[NSCandidateListTouchBarItem alloc]
-          initWithIdentifier:kTextSuggestionsItemsTouchId];
+          initWithIdentifier:kTextSuggestionsItemsTouchId]);
 
-  candidateListItem.delegate = self;
+  [candidateListItem setDelegate:self];
   if (selectionRange_.length)
-    candidateListItem.collapsed = YES;
+    [candidateListItem setCollapsed:YES];
 
   [candidateListItem setCandidates:suggestions_
                   forSelectedRange:selectionRange_
                           inString:text_];
 
-  return candidateListItem;
+  return candidateListItem.autorelease();
 }
 
 - (void)candidateListTouchBarItem:(NSCandidateListTouchBarItem*)anItem

chrome/browser/ui/cocoa/touchbar/text_suggestions_touch_bar_controller_unittest.mm

@@ -38,15 +38,11 @@ class TextSuggestionsTouchBarControllerTest : public CocoaTest {
 // Tests that the NSCandidateListTouchBarItem collapses properly.
 TEST_F(TextSuggestionsTouchBarControllerTest, CollapsedCandidateList) {
   if (@available(macOS 10.12.2, *)) {
-    base::scoped_nsobject<NSCandidateListTouchBarItem> item;
-
     [controller_ setSelectionRange:gfx::Range()];
-    item.reset([controller_ createCandidateListItem]);
-    EXPECT_FALSE([item isCollapsed]);
+    EXPECT_FALSE([[controller_ makeCandidateListItem] isCollapsed]);
 
     [controller_ setSelectionRange:gfx::Range(0, 1)];
-    item.reset([controller_ createCandidateListItem]);
-    EXPECT_TRUE([item isCollapsed]);
+    EXPECT_TRUE([[controller_ makeCandidateListItem] isCollapsed]);
   }
 }
 
@@ -142,4 +138,4 @@ TEST_F(TextSuggestionsTouchBarControllerTest, TouchBarMetrics) {
     histogram_tester.ExpectBucketCount("TouchBar.Default.Metrics",
                                        ui::TouchBarAction::TEXT_SUGGESTION, 1);
   }
-}
+}
\ No newline at end of file