Fix javac --incremental by using jmake for dependency analysis

build/config/android/config.gni

Index: build/config/android/config.gni
diff --git a/build/config/android/config.gni b/build/config/android/config.gni
index 1b777696dec4b63945dc53685f379910db609b75..18af3e51fd5575e7de0ea0380307ea5d1a586fc8 100644
--- a/build/config/android/config.gni
+++ b/build/config/android/config.gni
@@ -71,10 +71,16 @@ if (is_android) {
     disable_incremental_isolated_processes = false
 
     # Speed up incremental compiles by compiling only changed files.
-    incremental_javac = false
+    enable_incremental_javac = false
 
     # Speed up dexing using dx --incremental.
-    incremental_dx = true
+    enable_incremental_dx = true
+
+    # Neither of these should ever be used for release builds since they are
+    # somewhat experimental and dx --incremental is known to not produce
+    # byte-for-byte identical output.
+    assert(!(enable_incremental_dx && !is_debug))
+    assert(!(enable_incremental_javac && !is_debug))
   }
 
   # Host stuff -----------------------------------------------------------------