[Checkstyle] Update static variable and constant names to match style guides.

tools/android/checkstyle/chromium-style-5.0.xml

Index: tools/android/checkstyle/chromium-style-5.0.xml
diff --git a/tools/android/checkstyle/chromium-style-5.0.xml b/tools/android/checkstyle/chromium-style-5.0.xml
index a760b29c91abf4f1520be6a6d2322259bac24eb7..7a50d31555a8e093dc4e0614dc15bf591e95916a 100644
--- a/tools/android/checkstyle/chromium-style-5.0.xml
+++ b/tools/android/checkstyle/chromium-style-5.0.xml
@@ -45,7 +45,7 @@
       <property name="severity" value="warning"/>
     </module>
     <module name="ConstantName">
-      <property name="severity" value="warning"/>
+      <property name="severity" value="error"/>
       <property name="format" value="^([A-Z][A-Z0-9]*(_[A-Z0-9]+)*)|(s[A-Z][a-zA-Z0-9]*)$"/>
       <message key="name.invalidPattern" value="Static final field names must either be all caps (e.g. int HEIGHT_PX) for 'true' constants, or start with s (e.g. AtomicInteger sNextId or Runnable sSuspendTask) for fields with mutable state or that don't 'feel' like constants."/>
     </module>
@@ -58,6 +58,7 @@
     </module>
     <!-- Static field names start with s. -->
     <module name="StaticVariableName">
+        <property name="severity" value="error"/>
         <property name="format" value="^s[A-Z][a-zA-Z0-9]*$"/>
         <property name="applyToPublic" value="false"/>
         <message key="name.invalidPattern" value="Static field names start with s."/>