New C++ -> Java enum build rule + parser/generator.

ui/android/BUILD.gn

 import("//build/config/android/rules.gni")
 
 assert(is_android)
 
-java_cpp_template("window_open_disposition_srcjar") {
-  package_name = "org/chromium/ui"
+java_cpp_enum("java_enums_srcjar") {
   sources = [
-    "java/WindowOpenDisposition.template",
+    "../base/window_open_disposition.h",
+    "../gfx/android/java_bitmap.h",
   ]
-  inputs = [
-    "../base/window_open_disposition_list.h"
+  outputs = [
+    "org/chromium/ui/WindowOpenDisposition.java",
+    "org/chromium/ui/gfx/BitmapFormat.java",
   ]
 }
 
-java_cpp_template("bitmap_format_srcjar") {
-  package_name = "org/chromium/ui/gfx"
-  sources = [
-    "java/BitmapFormat.template",
-  ]
-  inputs = [
-    "../gfx/android/bitmap_config_list.h"
-  ]
-}
-
 java_strings_grd("ui_strings_grd") {
   grd_file = "java/strings/android_ui_strings.grd"
   outputs = [
     "values-am/android_ui_strings.xml",
     "values-ar/android_ui_strings.xml",
     "values-bg/android_ui_strings.xml",
     "values-ca/android_ui_strings.xml",
     "values-cs/android_ui_strings.xml",
     "values-da/android_ui_strings.xml",
     "values-de/android_ui_strings.xml",
@@ skipping 79 matching lines @@
     "java/src/org/chromium/ui/gfx/DeviceDisplayInfo.java",
     "java/src/org/chromium/ui/gfx/ViewConfigurationHelper.java",
     "java/src/org/chromium/ui/gl/SurfaceTextureListener.java",
     "java/src/org/chromium/ui/gl/SurfaceTexturePlatformWrapper.java",
   ]
   deps = [
     ":ui_java_resources",
     "//base:base_java",
   ]
   srcjar_deps = [
-    ":window_open_disposition_srcjar",
-    ":bitmap_format_srcjar",
+    ":java_enums_srcjar",
   ]
 }