Revert "Use autolayout in LocationBarView"

This reverts commit 46e29e03 (breaks ios tests).

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> Use autolayout in LocationBarView
> 
> Uses autolayout in LocationBarView to position the omnibox textfield.
> 
> Bug: 
> Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet
> Change-Id: If9f0f9ec65624785617bb3820d56509845f97e5e
> Reviewed-on: https://chromium-review.googlesource.com/709215
> Commit-Queue: Stepan Khapugin <stkhapugin@chromium.org>
> Reviewed-by: Rohit Rao (ping after 24h) <rohitrao@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#515911}

TBR=rohitrao@chromium.org,stkhapugin@chromium.org

Change-Id: I3a935b9525fb504af1e41314ef3d5b9f7aefa697
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet
Reviewed-on: https://chromium-review.googlesource.com/766047Reviewed-by: Stepan Khapugin <stkhapugin@chromium.org>
Commit-Queue: Stepan Khapugin <stkhapugin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#515931}

ios/chrome/browser/ui/omnibox/omnibox_text_field_ios.mm

@@ -110,19 +110,14 @@ NSString* const kOmniboxFadeAnimationKey = @"OmniboxFadeAnimation";
                                                   textColor:textColor
                                                   tintColor:tintColor];
     [self addSubview:_textField];
-
-    [NSLayoutConstraint activateConstraints:@[
-      [_textField.leftAnchor constraintEqualToAnchor:self.leftAnchor],
-      [_textField.rightAnchor constraintEqualToAnchor:self.rightAnchor],
-      [_textField.topAnchor constraintEqualToAnchor:self.topAnchor],
-      [_textField.bottomAnchor constraintEqualToAnchor:self.bottomAnchor],
-    ]];
-
-    _textField.translatesAutoresizingMaskIntoConstraints = NO;
   }
   return self;
 }
 
+- (void)layoutSubviews {
+  [super layoutSubviews];
+  self.textField.frame = self.bounds;
+}
 
 @end