Rather than requiring early registration for all method id, we can initialize
them lazily as required.
This solves the problem of building against SDK X but running against X - 1.
Also adds a microbenchmark to ensure there are no considerable regressions.
Results are a bit variable, but it hovers over:
[ERROR:jni_android_unittest.cc(125)] JNI LazyMethodIDCall (us) 1983
[ERROR:jni_android_unittest.cc(127)] JNI MethodIDCall (us) 1862
BUG=152987
TEST=JNIAndroidMicrobenchmark.MethodId
TBR=akalin
Review URL: https://chromiumcodereview.appspot.com/11038015
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@162186 0039d316-1c4b-4281-b951-d872f2087c98