[Chips] Update MDCChipField to move long text from a line with chips …

…to a new line. (material-components#9826)

Call layoutSubviews on textChanged to reposition MDCChipField's textField if:

1. The textField is on the same line as chips and becomes too long to fit
1. The textField is on the line below chips but can fit on the line with chips

Fixes #9006 

Before:
![before 2020-03-03 15_08_50](https://user-images.githubusercontent.com/581764/75815310-2e680000-5d61-11ea-8623-62719a0d0f3a.gif)

After:
![after 2020-03-03 15_10_39](https://user-images.githubusercontent.com/581764/75815323-3031c380-5d61-11ea-8468-69b70d4921ab.gif)

components/Chips/src/MDCChipField.m

@@ -615,6 +615,21 @@ - (BOOL)textFieldShouldReturn:(UITextField *)textField {
 - (void)textFieldDidChange {
   [self deselectAllChips];
   [self createNewChipWithTextField:self.textField delimiter:MDCChipFieldDelimiterSpace];
+  CGRect lastChipFrame = self.chips.lastObject.frame;
+  if (!CGRectIsEmpty(lastChipFrame)) {
+    BOOL isTextTooWide = [self textInputDesiredWidth] >= [self availableWidthForTextInput];
+    BOOL isTextFieldOnSameLineAsChips =
+        CGRectGetMidY(self.textField.frame) == CGRectGetMidY(lastChipFrame);
+    if (isTextTooWide && isTextFieldOnSameLineAsChips) {
+      // The text is on the same line as the chips and doesn't fit
+      // Trigger layout to move the text field down to the next line
+      [self setNeedsLayout];
+    } else if (!isTextTooWide && !isTextFieldOnSameLineAsChips) {
+      // The text is on the line below the chips but can fit on the same line
+      // Trigger layout to move the text field up to the previous line
+      [self setNeedsLayout];
+    }
+  }
 
   if ([self.delegate respondsToSelector:@selector(chipField:didChangeInput:)]) {
     [self.delegate chipField:self didChangeInput:[self.textField.text copy]];
@@ -740,6 +755,8 @@ - (CGFloat)availableWidthForTextInput {
 }
 
 // The width of the text input + the clear button.
+// Used to determine whether the text field can fit on a line with chips or whether it gets its
+// own line.
 - (CGFloat)textInputDesiredWidth {
   UIFont *font = self.textField.placeholderLabel.font;
   CGRect placeholderDesiredRect = [self.textField.text