[iOS][DarkMode] Add gray dynamic colors

Bug: 974255
Change-Id: I347ef90bdb8be466daed846c7e7d790cc6c8da7c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1700062
Commit-Queue: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Auto-Submit: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Reviewed-by: Robbie Gibson <rkgibson@google.com>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#676903}

ios/chrome/common/colors/UIColor+cr_semantic_colors.h

@@ -31,6 +31,13 @@
 @property(class, nonatomic, readonly) UIColor* cr_separatorColor;
 @property(class, nonatomic, readonly) UIColor* cr_opaqueSeparatorColor;
 
+// Gray Colors
+@property(class, nonatomic, readonly) UIColor* cr_systemGray2Color;
+@property(class, nonatomic, readonly) UIColor* cr_systemGray3Color;
+@property(class, nonatomic, readonly) UIColor* cr_systemGray4Color;
+@property(class, nonatomic, readonly) UIColor* cr_systemGray5Color;
+@property(class, nonatomic, readonly) UIColor* cr_systemGray6Color;
+
 @end
 
 #endif  // IOS_CHROME_COMMON_COLORS_UICOLOR_CR_SEMANTIC_COLORS_H_

ios/chrome/common/colors/UIColor+cr_semantic_colors.mm

@@ -102,4 +102,71 @@
                          alpha:1];
 }
 
+#pragma mark - Gray Colors
+
++ (UIColor*)cr_systemGray2Color {
+#if defined(__IPHONE_13_0) && (__IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_13_0)
+  if (@available(iOS 13, *)) {
+    return UIColor.systemGray2Color;
+  }
+#endif
+  // This is the value for systemGray2Color in light mode.
+  return [UIColor colorWithRed:174 / (CGFloat)0xFF
+                         green:174 / (CGFloat)0xFF
+                          blue:178 / (CGFloat)0xFF
+                         alpha:1];
+}
+
++ (UIColor*)cr_systemGray3Color {
+#if defined(__IPHONE_13_0) && (__IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_13_0)
+  if (@available(iOS 13, *)) {
+    return UIColor.systemGray3Color;
+  }
+#endif
+  // This is the value for systemGray3Color in light mode.
+  return [UIColor colorWithRed:199 / (CGFloat)0xFF
+                         green:199 / (CGFloat)0xFF
+                          blue:204 / (CGFloat)0xFF
+                         alpha:1];
+}
+
++ (UIColor*)cr_systemGray4Color {
+#if defined(__IPHONE_13_0) && (__IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_13_0)
+  if (@available(iOS 13, *)) {
+    return UIColor.systemGray4Color;
+  }
+#endif
+  // This is the value for systemGray4Color in light mode.
+  return [UIColor colorWithRed:209 / (CGFloat)0xFF
+                         green:209 / (CGFloat)0xFF
+                          blue:214 / (CGFloat)0xFF
+                         alpha:1];
+}
+
++ (UIColor*)cr_systemGray5Color {
+#if defined(__IPHONE_13_0) && (__IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_13_0)
+  if (@available(iOS 13, *)) {
+    return UIColor.systemGray5Color;
+  }
+#endif
+  // This is the value for systemGray5Color in light mode.
+  return [UIColor colorWithRed:229 / (CGFloat)0xFF
+                         green:229 / (CGFloat)0xFF
+                          blue:234 / (CGFloat)0xFF
+                         alpha:1];
+}
+
++ (UIColor*)cr_systemGray6Color {
+#if defined(__IPHONE_13_0) && (__IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_13_0)
+  if (@available(iOS 13, *)) {
+    return UIColor.systemGray6Color;
+  }
+#endif
+  // This is the value for systemGray6Color in light mode.
+  return [UIColor colorWithRed:242 / (CGFloat)0xFF
+                         green:242 / (CGFloat)0xFF
+                          blue:247 / (CGFloat)0xFF
+                         alpha:1];
+}
+
 @end