Add support for proguard preprocessing.

third_party/guava/proguard.pro

Index: third_party/guava/proguard.pro
diff --git a/third_party/guava/proguard.pro b/third_party/guava/proguard.pro
new file mode 100644
index 0000000000000000000000000000000000000000..27e5a4fd4d17a169d03e8beda477953e95b5a7e1
--- /dev/null
+++ b/third_party/guava/proguard.pro
@@ -0,0 +1,22 @@
+

[nyquist, 2013/08/14 22:19:10]

Nit: Unecessary newline.

[nyquist, 2013/08/14 23:24:12]

Done.

+-keep class com.google.common.base.** {
+  *;
+}
+
+-keep class com.google.common.annotations.** {
+  *;
+}
+
+-keep class com.google.common.collect.** {
+  *;
+}
+
+-keepattributes Signature
+
+# Don't complain about usage of sun.misc.Unsafe. Guava imports this,
+# but does not use it unless it exists. The gyp-target for guava is:
+# src/third_party/guava/guava.gyp:guava_javalib
+-dontwarn sun.misc.Unsafe
+# Striped64 uses reflection to access some local fields.
+-dontnote com.google.common.cache.Striped64
+-dontnote com.google.common.cache.Striped64$Cell

[nyquist, 2013/08/14 22:19:10]

Nit: Missing newline at end of file.

[nyquist, 2013/08/14 23:24:12]

Done.