Disable Proguard for the SampleBrowerPlugin

The native plugin library makes calls into java files that are
not often stripped out when Proguard optimizes the package.

Change-Id: I6ce8867dc9fa23e8a6adcc8daf9c8fb75f83c16d
diff --git a/samples/BrowserPlugin/Android.mk b/samples/BrowserPlugin/Android.mk
index 16047d5..827700f 100644
--- a/samples/BrowserPlugin/Android.mk
+++ b/samples/BrowserPlugin/Android.mk
@@ -24,6 +24,8 @@
 
 LOCAL_SRC_FILES := $(call all-subdir-java-files)
 
+LOCAL_PROGUARD_ENABLED := disabled
+
 LOCAL_PACKAGE_NAME := SampleBrowserPlugin
 
 LOCAL_JNI_SHARED_LIBRARIES := libsampleplugin