[Banner] fix layout margin not being considered for all layout styles. (

#7956)

closes https://github.com/material-components/material-components-ios/issues/7959

There was a misalignment issue  on the horizontal axis for non single line style banner. `widthLimit` should be used in all layout styles.

components/Banner/src/MDCBannerView.m

@@ -327,15 +327,13 @@ - (void)deactivateAllConstraints {
 - (CGSize)sizeThatFits:(CGSize)size {
   MDCBannerViewLayoutStyle layoutStyle = [self layoutStyleForSizeToFit:size];
   CGFloat frameHeight = 0.0f;
+  CGSize contentSize = [self contentSizeForLayoutSize:size];
   switch (layoutStyle) {
     case MDCBannerViewLayoutStyleSingleRow: {
       frameHeight += kTopPaddingSmall + kBottomPadding;
-      CGFloat widthLimit = size.width;
-      CGFloat marginsPadding = self.layoutMargins.left + self.layoutMargins.right;
-      widthLimit -= marginsPadding;
-      widthLimit -= (kLeadingPadding + kTrailingPadding);
       [self.leadingButton sizeToFit];
       CGFloat buttonWidth = CGRectGetWidth(self.leadingButton.frame);
+      CGFloat widthLimit = contentSize.width;
       widthLimit -= (buttonWidth + kHorizontalSpaceBetweenTextLabelAndButton);
       if (!self.imageView.hidden) {
         widthLimit -= kImageViewSideLength;
@@ -352,15 +350,15 @@ - (CGSize)sizeThatFits:(CGSize)size {
     }
     case MDCBannerViewLayoutStyleMultiRowAlignedButton: {
       frameHeight += kTopPaddingLarge + kBottomPadding;
-      frameHeight += [self getFrameHeightOfImageViewAndTextLabelWithSizeToFit:size];
+      frameHeight += [self getFrameHeightOfImageViewAndTextLabelWithSizeToFit:contentSize];
       CGSize leadingButtonSize = [self.leadingButton sizeThatFits:CGSizeZero];
       CGSize trailingButtonSize = [self.trailingButton sizeThatFits:CGSizeZero];
       frameHeight += MAX(leadingButtonSize.height, trailingButtonSize.height);
       break;
     }
     case MDCBannerViewLayoutStyleMultiRowStackedButton: {
       frameHeight += kTopPaddingLarge + kBottomPadding;
-      frameHeight += [self getFrameHeightOfImageViewAndTextLabelWithSizeToFit:size];
+      frameHeight += [self getFrameHeightOfImageViewAndTextLabelWithSizeToFit:contentSize];
       CGSize leadingButtonSize = [self.leadingButton sizeThatFits:CGSizeZero];
       CGSize trailingButtonSize = [self.trailingButton sizeThatFits:CGSizeZero];
       frameHeight +=
@@ -460,10 +458,8 @@ - (MDCBannerViewLayoutStyle)layoutStyleForSizeToFit:(CGSize)sizeToFit {
   }
 
   MDCBannerViewLayoutStyle layoutStyle;
-  CGFloat remainingWidth = sizeToFit.width;
-  CGFloat marginsPadding = self.layoutMargins.left + self.layoutMargins.right;
-  remainingWidth -= marginsPadding;
-  remainingWidth -= (kLeadingPadding + kTrailingPadding);
+  CGSize contentSize = [self contentSizeForLayoutSize:sizeToFit];
+  CGFloat remainingWidth = contentSize.width;
   [self.leadingButton sizeToFit];
   if (self.trailingButton.hidden) {
     CGFloat buttonWidth = CGRectGetWidth(self.leadingButton.frame);
@@ -487,7 +483,7 @@ - (MDCBannerViewLayoutStyle)layoutStyleForSizeToFit:(CGSize)sizeToFit {
 
 - (CGFloat)getFrameHeightOfImageViewAndTextLabelWithSizeToFit:(CGSize)sizeToFit {
   CGFloat frameHeight = 0;
-  CGFloat remainingWidth = sizeToFit.width - kLeadingPadding - kTrailingPadding;
+  CGFloat remainingWidth = sizeToFit.width;
   CGSize textLabelSize = CGSizeZero;
   if (!self.imageView.hidden) {
     remainingWidth -= (kImageViewSideLength + kSpaceBetweenIconImageAndTextLabel);
@@ -501,6 +497,14 @@ - (CGFloat)getFrameHeightOfImageViewAndTextLabelWithSizeToFit:(CGSize)sizeToFit
   return frameHeight;
 }
 
+- (CGSize)contentSizeForLayoutSize:(CGSize)layoutSize {
+  CGFloat remainingWidth = layoutSize.width;
+  CGFloat marginsPadding = self.layoutMargins.left + self.layoutMargins.right;
+  remainingWidth -= marginsPadding;
+  remainingWidth -= (kLeadingPadding + kTrailingPadding);
+  return CGSizeMake(remainingWidth, layoutSize.height);
+}
+
 - (CGFloat)widthSumForButtons:(NSArray<__kindof UIButton *> *)buttons {
   CGFloat buttonsWidthSum = 0;
   for (UIButton *button in buttons) {

components/Banner/tests/snapshot/MDCBannerSnapshotTests.m

@@ -281,6 +281,37 @@ - (void)testMiddleLengthTextWithLargeLayoutMargin {
   [self generateSnapshotAndVerifyForView:self.bannerView];
 }
 
+- (void)testMiddleLengthTextAndStackedButtonsWithLargeLayoutMargin {
+  // Given
+  self.bannerView.textLabel.text = kBannerMiddleLengthText;
+  MDCButton *button1 = self.bannerView.leadingButton;
+  [button1 setTitle:@"Action1" forState:UIControlStateNormal];
+  [button1 setTitleColor:UIColor.blackColor forState:UIControlStateNormal];
+  button1.uppercaseTitle = YES;
+  MDCButton *button2 = self.bannerView.trailingButton;
+  [button2 setTitle:@"Action2" forState:UIControlStateNormal];
+  [button2 setTitleColor:UIColor.blackColor forState:UIControlStateNormal];
+  button2.uppercaseTitle = YES;
+  self.bannerView.bannerViewLayoutStyle = MDCBannerViewLayoutStyleMultiRowStackedButton;
+  self.bannerView.imageView.hidden = YES;
+
+  // When
+  if (@available(iOS 11.0, *)) {
+    NSDirectionalEdgeInsets directionalEdgeInsets = NSDirectionalEdgeInsetsZero;
+    directionalEdgeInsets.leading = kBannerLargeContentPadding;
+    directionalEdgeInsets.trailing = kBannerLargeContentPadding;
+    self.bannerView.directionalLayoutMargins = directionalEdgeInsets;
+  } else {
+    UIEdgeInsets margins = UIEdgeInsetsZero;
+    margins.left = kBannerLargeContentPadding;
+    margins.right = kBannerLargeContentPadding;
+    self.bannerView.layoutMargins = margins;
+  }
+
+  // Then
+  [self generateSnapshotAndVerifyForView:self.bannerView];
+}
+
 - (void)testSingleRowStyleLongTextWithSingleActionLTR {
   // When
   self.bannerView.textLabel.text = kBannerLongText;