Moving flags out of base_proguard_config make it usable by other .apks

android_webview/apk/java/proguard.flags

Index: android_webview/apk/java/proguard.flags
diff --git a/android_webview/apk/java/proguard.flags b/android_webview/apk/java/proguard.flags
index d4a0a47e26b72b6a2c2919df5d5c51a7697b340c..c94cca6949170eb92d63f2a1cc980610f42cbeb0 100644
--- a/android_webview/apk/java/proguard.flags
+++ b/android_webview/apk/java/proguard.flags
@@ -3,6 +3,24 @@
 # tables.
 -keepnames class *** { *; }
 
+# The following chart was created on Aug. 11, 2016, to decide on 3 optimization
+# passes.
+# optimization passes | time | .dex size |      dirty memory
+# -----------------------------------------------------------------
+#          1          | 0:13 |  1022588  |         97772
+#          2          | 0:17 |  1019200  |         97472
+#          3          | 0:18 |  1018472  |         97424
+#          4          | 0:21 |  1018392  |         97416
+#          5          | 0:26 |  1018360  |         97416
+-optimizationpasses 3
+
+# Class merging messes up stacktraces beyond the point of them being
+# deobfuscatable. If turned on, it would give us a 1% reduction in .dex size.
+-optimizations !class/merging/*
+
+# Allowing Proguard to change modifiers. This change shrinks the .dex size by
+# 3.7%.
+-allowaccessmodification
 
 # Keep the factory and its public members; it's the main entry point used by the
 # framework.