Support for return PC offset and frame size in JNI compiler.

For stack crawls we need the return PC and the size of frames, store
this information in the Method.

Change-Id: Ic616b4f78ca571c837e5c8473607285a7e8b58f0
diff --git a/src/calling_convention_arm.cc b/src/calling_convention_arm.cc
index 743445d..143d83b 100644
--- a/src/calling_convention_arm.cc
+++ b/src/calling_convention_arm.cc
@@ -78,6 +78,12 @@
   return RoundUp(frame_data_size + handle_area_size + SizeOfReturnValue(), 16);
 }
 
+size_t JniCallingConvention::ReturnPcOffset() {
+  // Link register is always the last value spilled, skip forward one word for
+  // the Method* then skip back one word to get the link register (ie +0)
+  return SpillAreaSize();
+}
+
 size_t JniCallingConvention::SpillAreaSize() {
   // Space for link register. For synchronized methods we need enough space to
   // save R1, R2 and R3 (R0 is the method register and always preserved)