[Modern] Update in-product help text bubble style

BUG=844570

Change-Id: I43a3d38a97718309fc781a09609641c9b3bc72d5
Reviewed-on: https://chromium-review.googlesource.com/1125081Reviewed-by: Becky Zhou <huayinz@chromium.org>
Commit-Queue: Theresa <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572321}

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

@@ -8,4 +8,4 @@
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:padding="16dp"
-    android:textAppearance="@style/WhiteBody" />
+    android:textAppearance="@style/WhiteTitle2" />

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

@@ -29,6 +29,6 @@
         android:id="@+id/message"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:textAppearance="@style/WhiteBody" />
+        android:textAppearance="@style/WhiteTitle2" />
 
 </LinearLayout>
\ No newline at end of file

chrome/android/java/res/values/dimens.xml

@@ -519,7 +519,7 @@
 
     <!-- TextBubble dimensions -->
     <dimen name="text_bubble_margin">4dp</dimen>
-    <dimen name="text_bubble_corner_radius">2dp</dimen>
+    <dimen name="text_bubble_corner_radius">8dp</dimen>
     <dimen name="text_bubble_arrow_width">20dp</dimen>
     <dimen name="text_bubble_arrow_height">10dp</dimen>
     <dimen name="text_bubble_menu_anchor_y_inset">14dp</dimen>