Upstream Chrome on iOS source code [4/11].

ios/chrome/browser/ui/contextual_search/contextual_search_highlighter_view.mm

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "ios/chrome/browser/ui/contextual_search/contextual_search_highlighter_view.h"
+
+#include "base/logging.h"
+#import "base/mac/scoped_nsobject.h"
+#import "ios/chrome/browser/ui/contextual_search/contextual_search_controller.h"
+
+@implementation ContextualSearchHighlighterView {
+  // Store size of the container view. If size change, text layout will likely
+  // change and should be updated.
+  CGSize _previousSize;
+
+  // Store values that were used last time the rects were drawn.
+  CGPoint _scroll;
+  CGFloat _zoom;
+  CGFloat _offset;
+
+  __unsafe_unretained id<ContextualSearchHighlighterDelegate> _delegate;
+}
+
+- (instancetype)initWithFrame:(CGRect)frame
+                     delegate:
+                         (id<ContextualSearchHighlighterDelegate>)delegate {
+  self = [super initWithFrame:frame];
+  if (self) {
+    [self setUserInteractionEnabled:NO];
+    [self setAutoresizingMask:UIViewAutoresizingFlexibleWidth |
+                              UIViewAutoresizingFlexibleHeight];
+    _previousSize = frame.size;
+    _delegate = delegate;
+  }
+  return self;
+}
+
+- (instancetype)initWithFrame:(CGRect)frame {
+  NOTREACHED();
+  return nil;
+}
+
+- (instancetype)initWithCoder:(NSCoder*)aDecoder {
+  NOTREACHED();
+  return nil;
+}
+
+- (void)layoutSubviews {
+  [super layoutSubviews];
+  if (!CGSizeEqualToSize(_previousSize, self.frame.size)) {
+    _previousSize = self.frame.size;
+    dispatch_async(dispatch_get_main_queue(), ^{
+      [_delegate updateHighlight];
+    });
+  }
+}
+
+- (void)highlightRects:(NSArray*)rects
+            withOffset:(CGFloat)offset
+                  zoom:(CGFloat)zoom
+                scroll:(CGPoint)scroll {
+  for (UIView* view : [self subviews]) {
+    [view removeFromSuperview];
+  }
+  for (NSValue* value in rects) {
+    CGRect rect = [value CGRectValue];
+    rect.origin.x *= zoom;
+    rect.origin.y *= zoom;
+    rect.size.width *= zoom;
+    rect.size.height *= zoom;
+    rect.origin.x -= scroll.x;
+    rect.origin.y += offset - scroll.y;
+    UIView* view = [[[UIView alloc] initWithFrame:rect] autorelease];
+    [self addSubview:view];
+    view.backgroundColor =
+        [UIColor colorWithRed:0.67 green:0.88 blue:0.96 alpha:0.6];
+  }
+  [[self superview] bringSubviewToFront:self];
+  _zoom = zoom;
+  _scroll = scroll;
+  _offset = offset;
+}
+
+- (void)setScroll:(CGPoint)newScroll
+             zoom:(CGFloat)newZoom
+           offset:(CGFloat)newOffset {
+  for (UIView* view : [self subviews]) {
+    CGRect oldFrame = [view frame];
+    CGRect newFrame;
+    CGFloat scaleAdjust = newZoom / _zoom;
+    newFrame.origin.x =
+        (oldFrame.origin.x + _scroll.x) * scaleAdjust - newScroll.x;
+    newFrame.origin.y =
+        (oldFrame.origin.y + _scroll.y - _offset) * scaleAdjust + newOffset -
+        newScroll.y;
+    newFrame.size.width = oldFrame.size.width * scaleAdjust;
+    newFrame.size.height = oldFrame.size.height * scaleAdjust;
+    [view setFrame:newFrame];
+  }
+  _scroll = newScroll;
+}
+
+- (CGRect)boundingRect {
+  CGRect bounding = CGRectNull;
+  for (UIView* view : [self subviews]) {
+    bounding = CGRectUnion(bounding, view.frame);
+  }
+  bounding.origin.x += _scroll.x;
+  bounding.origin.y += _scroll.y;
+  return bounding;
+}
+
+@end