Remove toolbar's blur colored background

This CL removes the background color on the blur content view.

Bug: 821375
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I2378bb075927bf5ba7ffd8a7a69bbc90c5328377
Reviewed-on: https://chromium-review.googlesource.com/960036
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Stepan Khapugin <stkhapugin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542800}

ios/chrome/browser/ui/toolbar/adaptive/primary_toolbar_view.mm

@@ -149,8 +149,6 @@
 - (void)setUpBlurredBackground {
   UIBlurEffect* blurEffect = self.buttonFactory.toolbarConfiguration.blurEffect;
   self.blur = [[UIVisualEffectView alloc] initWithEffect:blurEffect];
-  self.blur.contentView.backgroundColor =
-      self.buttonFactory.toolbarConfiguration.blurEffectBackgroundColor;
   [self addSubview:self.blur];
 
   self.contentView = self;

ios/chrome/browser/ui/toolbar/adaptive/secondary_toolbar_view.mm

@@ -85,9 +85,6 @@
 
   UIBlurEffect* blurEffect = self.buttonFactory.toolbarConfiguration.blurEffect;
   self.blur = [[UIVisualEffectView alloc] initWithEffect:blurEffect];
-  self.blur.contentView.backgroundColor =
-      self.buttonFactory.toolbarConfiguration.blurEffectBackgroundColor;
-
   [self addSubview:self.blur];
   self.blur.translatesAutoresizingMaskIntoConstraints = NO;
   AddSameConstraints(self.blur, self);

ios/chrome/browser/ui/toolbar/buttons/toolbar_configuration.h

@@ -22,9 +22,6 @@
 // Blur effect for the toolbar background.
 @property(nonatomic, readonly) UIBlurEffect* blurEffect;
 
-// Background color for the blur effect view.
-@property(nonatomic, readonly) UIColor* blurEffectBackgroundColor;
-
 // Background color of the NTP. Used to do as if the toolbar was transparent and
 // the NTP is visible behind it.
 @property(nonatomic, readonly) UIColor* NTPBackgroundColor;

ios/chrome/browser/ui/toolbar/buttons/toolbar_configuration.mm

@@ -35,16 +35,6 @@
   }
 }
 
-- (UIColor*)blurEffectBackgroundColor {
-  switch (self.style) {
-    case NORMAL:
-      return [UIColor colorWithWhite:kBlurBackgroundGrayscaleComponent
-                               alpha:kBlurBackgroundAlpha];
-    case INCOGNITO:
-      return nil;
-  }
-}
-
 - (UIColor*)NTPBackgroundColor {
   switch (self.style) {
     case NORMAL: