Fix padding issues in First Run Account screen.

Android support library has a bug b/20307607 that causes it
to ignore padding set in XML on older (API 16) Android devices.

BUG=469568

Review URL: https://codereview.chromium.org/1061473004

Cr-Commit-Position: refs/heads/master@{#325574}

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

@@ -102,8 +102,8 @@
             android:background="?attr/listChoiceBackgroundIndicator"
             android:gravity="start|center_vertical"
             android:textDirection="locale"
-            android:paddingStart="16dp"
-            android:paddingEnd="16dp"
+            android:paddingStart="@dimen/fre_button_padding"
+            android:paddingEnd="@dimen/fre_button_padding"
             android:text="@string/fre_skip_text"
             android:textAllCaps="true"
             android:textColor="@color/light_normal_color"
@@ -118,8 +118,8 @@
             android:background="?attr/listChoiceBackgroundIndicator"
             android:gravity="end|center_vertical"
             android:textDirection="locale"
-            android:paddingStart="16dp"
-            android:paddingEnd="16dp"
+            android:paddingStart="@dimen/fre_button_padding"
+            android:paddingEnd="@dimen/fre_button_padding"
             android:text="@string/choose_account_sign_in"
             android:textAllCaps="true"
             android:textColor="@color/light_active_color"

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

@@ -109,6 +109,7 @@
     <dimen name="account_chooser_infobar_item_height">80dp</dimen>
 
     <!-- First Run Experience and Welcome Page dimensions -->
+    <dimen name="fre_button_padding">16dp</dimen>
     <dimen name="fre_margin">24dp</dimen>
     <dimen name="fre_title_text_size">24sp</dimen>
     <dimen name="fre_button_text_size">14sp</dimen>

chrome/android/java/src/org/chromium/chrome/browser/firstrun/AccountFirstRunView.java

@@ -164,6 +164,11 @@ public class AccountFirstRunView extends FrameLayout
             }
         });
 
+        // A workaround for Android support library ignoring padding set in XML. b/20307607
+        int padding = getResources().getDimensionPixelSize(R.dimen.fre_button_padding);
+        ApiCompatibilityUtils.setPaddingRelative(mPositiveButton, padding, 0, padding, 0);
+        ApiCompatibilityUtils.setPaddingRelative(mNegativeButton, padding, 0, padding, 0);
+
         mDescriptionText = (TextView) findViewById(R.id.description);
         mDescriptionTextId = R.string.fre_account_choice_description;