[Unity][Android] Use wrap_content for sign-in buttons height

This CL replaces layout_height="36dp" for buttons in the sign-in screen
with layout_height="wrap_content". These buttons use TextButton and
FilledButton.Flat text styles, so they already have min height set to
36dp. Setting layout_height to wrap_content allows these buttons to grow
if font height is larger than 36dp.

Bug: 927425
Change-Id: I616c1a952b3a4aa9ab52c46a7c7aff47bc05c301
Reviewed-on: https://chromium-review.googlesource.com/c/1458209
Commit-Queue: Boris Sazonov <bsazonov@chromium.org>
Commit-Queue: Theresa <twellington@chromium.org>
Auto-Submit: Boris Sazonov <bsazonov@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#629987}

chrome/android/java/res/layout/signin_view.xml

@@ -147,7 +147,7 @@
             android:id="@+id/negative_button"
             style="@style/TextButton"
             android:layout_width="wrap_content"
-            android:layout_height="36dp"
+            android:layout_height="wrap_content"
             android:paddingStart="@dimen/fre_button_padding"
             android:paddingEnd="@dimen/fre_button_padding"
             tools:text="@string/no_thanks"/>
@@ -160,7 +160,7 @@
             android:id="@+id/positive_button"
             style="@style/FilledButton.Flat"
             android:layout_width="wrap_content"
-            android:layout_height="36dp"
+            android:layout_height="wrap_content"
             android:paddingStart="@dimen/fre_button_padding"
             android:paddingEnd="@dimen/fre_button_padding"
             tools:text="@string/signin_accept_button"/>
@@ -168,7 +168,7 @@
             android:id="@+id/more_button"
             style="@style/TextButton"
             android:layout_width="wrap_content"
-            android:layout_height="36dp"
+            android:layout_height="wrap_content"
             android:drawableEnd="@drawable/down_arrow"
             android:drawablePadding="8dp"
             android:visibility="gone"