Turn all ErrorProne errors into warnings.

Change-Id: I302d0832914b3159fea8bf71708c176d2c1c5706
diff --git a/dev/BUILD b/dev/BUILD
index 701ceb4..ae0a279 100644
--- a/dev/BUILD
+++ b/dev/BUILD
@@ -129,10 +129,7 @@
     srcs = glob(["core/src/**/*.java"]),
     compatible_with = ["//buildenv/target:appengine"],
     javacopts = [
-        "-Xep:MissingCasesInEnumSwitch:OFF",
-        "-Xep:FallThrough:OFF",
-        "-Xep:ReturnValueIgnored:OFF",
-        "-Xep:EqualsIncompatibleType:OFF",
+        "-XepAllErrorsAsWarnings",
     ],
     deps = [
         ":compiler.standalone.super",
@@ -205,10 +202,7 @@
     ),
     compatible_with = ["//buildenv/target:appengine"],
     javacopts = [
-        "-Xep:MissingCasesInEnumSwitch:OFF",
-        "-Xep:FallThrough:OFF",
-        "-Xep:ReturnValueIgnored:OFF",
-        "-Xep:EqualsIncompatibleType:OFF",
+        "-XepAllErrorsAsWarnings",
     ],
     deps = [
         ":compiler.standalone.super",
@@ -302,12 +296,7 @@
         "core/test/**/*.java",
     ]),
     javacopts = [
-        "-Xep:MissingCasesInEnumSwitch:OFF",
-        "-Xep:SelfComparison:OFF",
-        "-Xep:SelfEquals:OFF",
-        "-Xep:FallThrough:OFF",
-        "-Xep:ReturnValueIgnored:OFF",
-        "-Xep:EqualsIncompatibleType:OFF",
+        "-XepAllErrorsAsWarnings",
     ],
     deps = [
         ":compiler.standalone.super",
diff --git a/dev/codeserver/BUILD b/dev/codeserver/BUILD
index 531337b..76d4db7 100644
--- a/dev/codeserver/BUILD
+++ b/dev/codeserver/BUILD
@@ -28,6 +28,9 @@
 java_library(
     name = "codeserver-bare",
     srcs = glob(["java/**/*.java"]),
+    javacopts = [
+        "-XepAllErrorsAsWarnings",
+    ],
     resources = glob([
         "java/**/*.html",
         "java/**/*.ico",
diff --git a/user/BUILD b/user/BUILD
index 33dd652..cdf4dd7 100644
--- a/user/BUILD
+++ b/user/BUILD
@@ -98,9 +98,7 @@
     ),
     compatible_with = ["//buildenv/target:appengine"],
     javacopts = [
-        "-Xep:FutureReturnValueIgnored:OFF",
-        "-Xep:MissingCasesInEnumSwitch:OFF",
-        "-Xep:EqualsIncompatibleType:OFF",
+        "-XepAllErrorsAsWarnings",
     ],
     plugins = [
         "//java/com/google/devtools/build/buildjar/plugin/gwt",
@@ -140,7 +138,9 @@
         "src/com/google/gwt/user/server/Base64Utils.java",
     ],
     compatible_with = ["//buildenv/target:appengine"],
-    javacopts = ["-Xep:MissingCasesInEnumSwitch:OFF"],
+    javacopts = [
+        "-XepAllErrorsAsWarnings",
+    ],
     deps = [
         "//third_party/java_src/gwt/svn/trunk/dev:requestfactory-apt-deps",
     ],
@@ -416,7 +416,9 @@
         ] + DTO_SRCS + JVM_REGEXP_SRCS,
     ),
     compatible_with = ["//buildenv/target:appengine"],
-    javacopts = ["-Xep:EqualsIncompatibleType:OFF"],
+    javacopts = [
+        "-XepAllErrorsAsWarnings",
+    ],
     deps = [
         ":gwt-dto-serializers",
         ":gwt-javaemul-annotations",
@@ -547,16 +549,7 @@
         "//third_party/java_src/gwt/svn/trunk/dev:dev-test-code",
     ],
     javacopts = [
-        "-Xep:CheckReturnValue:OFF",
-        "-Xep:DeadThread:OFF",
-        "-Xep:ReturnValueIgnored:OFF",
-        "-Xep:SelfComparison:OFF",  # go/self-comparison-lsc
-        "-Xep:SelfEquals:OFF",  # go/self-equals-lsc
-        "-Xep:IdentityBinaryExpression:OFF",
-        "-Xep:LoopConditionChecker:OFF",
-        "-Xep:EqualsIncompatibleType:OFF",
-        "-Xep:LogicalAssignment:OFF",
-        "-Xep:ComplexBooleanConstant:OFF",
+        "-XepAllErrorsAsWarnings",
     ],
     deps = [
         "//third_party/java/jsr305_annotations",