Switch protoc javastream plugin to using explicit path

The previous PATH=$PATH:out/... logic was incorrect, since the version
in $PATH would override the one out. And now that we're limiting what's
accessible via $PATH, that caused an error.

Instead, ensure that all protoc plugins are specified explicitly with
--plugin, then remove the PATH modification.

Test: cd frameworks/base/cmds/am; mma    (with protoc-gen-javastream in $PATH)
Change-Id: I6690727504f67f84fdc95ed93eabdf3351e5cb0b
diff --git a/core/java_common.mk b/core/java_common.mk
index e1ec30b..860d73c 100644
--- a/core/java_common.mk
+++ b/core/java_common.mk
@@ -80,6 +80,7 @@
 $(proto_java_sources_file_stamp): PRIVATE_PROTO_INCLUDES := $(TOP)
 $(proto_java_sources_file_stamp): PRIVATE_PROTO_SRC_FILES := $(proto_sources_fullpath)
 $(proto_java_sources_file_stamp): PRIVATE_PROTO_JAVA_OUTPUT_DIR := $(proto_java_sources_dir)
+$(proto_java_sources_file_stamp): PRIVATE_PROTOC_FLAGS := $(LOCAL_PROTOC_FLAGS)
 ifeq ($(LOCAL_PROTOC_OPTIMIZE_TYPE),micro)
 $(proto_java_sources_file_stamp): PRIVATE_PROTO_JAVA_OUTPUT_OPTION := --javamicro_out
 else
@@ -88,13 +89,13 @@
   else
     ifeq ($(LOCAL_PROTOC_OPTIMIZE_TYPE),stream)
 $(proto_java_sources_file_stamp): PRIVATE_PROTO_JAVA_OUTPUT_OPTION := --javastream_out
+$(proto_java_sources_file_stamp): PRIVATE_PROTOC_FLAGS += --plugin=$(HOST_OUT_EXECUTABLES)/protoc-gen-javastream
 $(proto_java_sources_file_stamp): $(HOST_OUT_EXECUTABLES)/protoc-gen-javastream
     else
 $(proto_java_sources_file_stamp): PRIVATE_PROTO_JAVA_OUTPUT_OPTION := --java_out
     endif
   endif
 endif
-$(proto_java_sources_file_stamp): PRIVATE_PROTOC_FLAGS := $(LOCAL_PROTOC_FLAGS)
 $(proto_java_sources_file_stamp): PRIVATE_PROTO_JAVA_OUTPUT_PARAMS := $(if $(filter lite,$(LOCAL_PROTOC_OPTIMIZE_TYPE)),lite$(if $(LOCAL_PROTO_JAVA_OUTPUT_PARAMS),:,),)$(LOCAL_PROTO_JAVA_OUTPUT_PARAMS)
 $(proto_java_sources_file_stamp) : $(proto_sources_fullpath) $(PROTOC)
 	$(call transform-proto-to-java)