Add a new Dart API call Dart_GetNativeFieldOfArgument

Add a new Dart API call Dart_GetNativeFieldOfArgument
which combines Dart_GetNativeArgument and Dart_GetNativeInstanceField

Dartium always gets the receiver by first getting the NativeArgument
corresponding to 0 using Dart_GetNativeArgument and then invokes
Dart_GetNativeInstanceField on the returned handle to get the native
field corresponding to the native DOM element.

When Dartium is changed to use this combined API call the numbers for a
sample Dromaeo-drt benchmark is as follows:

Dromaeo-drt getAttribute runs-per-second 653.0
Dromaeo-drt element_property_access runs-per-second 579.0
Dromaeo-drt setAttribute runs-per-second 396.0
Dromaeo-drt element_property_assignment runs-per-second 539.0

When the old API calls are used:
Dromaeo-drt getAttribute runs-per-second 596.0
Dromaeo-drt element_property_access runs-per-second 528.0
Dromaeo-drt setAttribute runs-per-second 385.0
Dromaeo-drt element_property_assignment runs-per-second 513.49

R=srdjan@google.com

Committed: https://code.google.com/p/dart/source/detail?r=25354

[srdjan, 2013-07-23 18:13:58]

lgtm

[siva, 2013-07-23 18:57:14]

Committed patchset #3 manually as r25354 (presubmit successful).