Frameworks/base: Add is64Bit method to Process

Add a public method to Process to query whether the current runtime
is running in 64-bit mode.

Bug: 21069469
Change-Id: Ifaf4251f05bbe5eba135fa977190e475632856bd

api/current.txt

@@ -23461,6 +23461,7 @@ package android.os {
     method public static final int getGidForName(java.lang.String);
     method public static final int getThreadPriority(int) throws java.lang.IllegalArgumentException;
     method public static final int getUidForName(java.lang.String);
+    method public static final boolean is64Bit();
     method public static final void killProcess(int);
     method public static final int myPid();
     method public static final int myTid();

api/system-current.txt

@@ -25387,6 +25387,7 @@ package android.os {
     method public static final int getGidForName(java.lang.String);
     method public static final int getThreadPriority(int) throws java.lang.IllegalArgumentException;
     method public static final int getUidForName(java.lang.String);
+    method public static final boolean is64Bit();
     method public static final void killProcess(int);
     method public static final int myPid();
     method public static final int myTid();

core/java/android/os/Process.java

@@ -21,6 +21,7 @@ import android.net.LocalSocketAddress;
 import android.system.Os;
 import android.util.Log;
 import com.android.internal.os.Zygote;
+import dalvik.system.VMRuntime;
 import java.io.BufferedWriter;
 import java.io.DataInputStream;
 import java.io.IOException;
@@ -744,7 +745,14 @@ public class Process {
      * @return  Returns the number of milliseconds this process has return.
      */
     public static final native long getElapsedCpuTime();
-    
+
+    /**
+     * Returns true if the current process is a 64-bit runtime.
+     */
+    public static final boolean is64Bit() {
+        return VMRuntime.getRuntime().is64Bit();
+    }
+
     /**
      * Returns the identifier of this process, which can be used with
      * {@link #killProcess} and {@link #sendSignal}.