[iOS] Replace background image with a uniform color.

ios/chrome/browser/ui/background_generator.mm

 // Copyright 2012 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.
 
 #include "ios/chrome/browser/ui/background_generator.h"
 
 #import <QuartzCore/QuartzCore.h>
 #include <stddef.h>
 
 #include "base/mac/bundle_locations.h"
 #include "base/mac/foundation_util.h"
 #include "base/mac/scoped_cftyperef.h"
 #import "ios/chrome/browser/ui/ui_util.h"
+#import "ios/third_party/material_components_ios/src/components/Palettes/src/MaterialPalettes.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 // This is a utility function that may be used as a standalone helper function
 // to generate a radial gradient UIImage.
 UIImage* GetRadialGradient(CGRect backgroundRect,
                            CGPoint centerPoint,
                            CGFloat radius,
@@ skipping 20 matching lines @@
         CGPointMake(centerPoint.x - logoImage.size.width / 2.0,
                     centerPoint.y - logoImage.size.height / 2.0));
     [logoImage drawAtPoint:corner];
   }
   UIImage* background = UIGraphicsGetImageFromCurrentImageContext();
   UIGraphicsEndImageContext();
   return background;
 }
 
 void InstallBackgroundInView(UIView* view) {
-  UIImageView* imageView = [[UIImageView alloc] initWithFrame:view.bounds];
-  imageView.image = [UIImage imageNamed:@"stack_view_background_noise.jpg"];
-  imageView.contentMode = UIViewContentModeScaleAspectFill;
-  imageView.autoresizingMask =
-      UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;
-  [view insertSubview:imageView atIndex:0];
+  [view setBackgroundColor:[[MDCPalette greyPalette] tint900]];
 }