Update isPasswordSuggestion to match style.

Actually made it into a method instead since I felt asking a
CWVAutofillSuggestion for its property passwordSuggestion is kind of
confusing. As a method I think it's more clear.

Change-Id: I3eb32cfff01236f099dcda720a812bdaa0f78c20
Reviewed-on: https://chromium-review.googlesource.com/c/1347101
Commit-Queue: John Wu <jzw@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610204}

ios/web_view/internal/autofill/cwv_autofill_suggestion.mm

@@ -14,13 +14,14 @@
 #error "This file requires ARC support."
 #endif
 
-@implementation CWVAutofillSuggestion
+@implementation CWVAutofillSuggestion {
+  BOOL _isPasswordSuggestion;
+}
 
 @synthesize formSuggestion = _formSuggestion;
 @synthesize formName = _formName;
 @synthesize fieldIdentifier = _fieldIdentifier;
 @synthesize frameID = _frameID;
-@synthesize isPasswordSuggestion = _isPasswordSuggestion;
 
 - (instancetype)initWithFormSuggestion:(FormSuggestion*)formSuggestion
                               formName:(NSString*)formName
@@ -59,6 +60,10 @@
       .ToUIImage();
 }
 
+- (BOOL)isPasswordSuggestion {
+  return _isPasswordSuggestion;
+}
+
 #pragma mark - NSObject
 
 - (NSString*)debugDescription {

ios/web_view/internal/autofill/cwv_autofill_suggestion_unittest.mm

@@ -41,7 +41,7 @@ TEST_F(CWVAutofillSuggestionTest, Initialization) {
   EXPECT_NSEQ(formSuggestion.displayDescription, suggestion.displayDescription);
   EXPECT_NSEQ(formSuggestion.value, suggestion.value);
   EXPECT_EQ(formSuggestion, suggestion.formSuggestion);
-  EXPECT_FALSE(suggestion.isPasswordSuggestion);
+  EXPECT_FALSE([suggestion isPasswordSuggestion]);
 }
 
 }  // namespace ios_web_view

ios/web_view/public/cwv_autofill_suggestion.h

@@ -60,11 +60,11 @@ CWV_EXPORT
 // credit card network icon.
 @property(nonatomic, readonly, nullable) UIImage* icon;
 
-// YES if this is a password autofill suggestion.
-@property(nonatomic, readonly) BOOL isPasswordSuggestion;
-
 - (instancetype)init NS_UNAVAILABLE;
 
+// YES if this is a password autofill suggestion.
+- (BOOL)isPasswordSuggestion;
+
 @end
 
 NS_ASSUME_NONNULL_END