Create a transition API for the debug message handler

Create a transition API for the debug message handler.

Kept the previous message handler API to avoid breaking clients depending on it.

The new message handler API uses a new name ending with 2.

Committed: http://code.google.com/p/v8/source/detail?r=1816

[Søren Thygesen Gjesse, 2009-04-29 12:17:46]

This is a temporary solution to avoid breaking current clients and keep the new
debugger message handler interface (with a new name).

[yurys, 2009-04-29 12:36:08]

http://codereview.chromium.org/100158/diff/1/3
File include/v8-debug.h (right):

http://codereview.chromium.org/100158/diff/1/3#newcode205
Line 205: static void SetMessageHandler2(MessageHandler2 handler);
When all clients are switched to the new message handler we will need to remove
the old one and rename SetMessageHandler2 to SetMessageHandler which will break
the code anyway. Consider switching to the new API without this intermediate
step.

[Mads Ager (chromium), 2009-04-29 12:49:30]

LGTM

This is rather heavy though as Yury points out.  However, we do need to keep the
V8 latest builders running so we can catch regressions.  When we get ready to
push to trunk, I will let you know so we can revert this change and have a
chromium side patch ready.

[Søren Thygesen Gjesse, 2009-04-29 13:24:15]

http://codereview.chromium.org/100158/diff/1/3
File include/v8-debug.h (right):

http://codereview.chromium.org/100158/diff/1/3#newcode205
Line 205: static void SetMessageHandler2(MessageHandler2 handler);
On 2009/04/29 12:36:08, Yury Semikhatsky wrote:
> When all clients are switched to the new message handler we will need to
remove
> the old one and rename SetMessageHandler2 to SetMessageHandler which will
break
> the code anyway. Consider switching to the new API without this intermediate
> step.

I agree that this is not optimal, but we need to keep the Webkit (V8-Latest)
builder happy so that we can catch any regressions before pushing to trunk. This
API incompatibility is actually such a regression.

When we push to trunk with the rename from MessageHandler2 -> MessageHandler the
DEPS roll and the client changes in Chromium can be done as a single commit.