Add profiling to debugger

This CL adds profiling to the debugger providing SK_PICTURE_PROFILING_STUBS is defined.

The SkPicture-derived classes in SkDebuggerGUI.cpp are specific to their usage in this app. In particular, they only override the ctor required for this app. Using them in a more general manner may produce unexpected results.

[DerekS, 2012-11-13 21:41:49]

https://codereview.appspot.com/6817114/diff/10001/debugger/QT/SkDebuggerGUI.cpp
File debugger/QT/SkDebuggerGUI.cpp (right):

https://codereview.appspot.com/6817114/diff/10001/debugger/QT/SkDebuggerGUI.c...
debugger/QT/SkDebuggerGUI.cpp:187: class SkTimedPlaybackPicture : public
SkPicture {
why not call it SkTimedPicture?  The current form is really similar to the class
defined directly above.

https://codereview.appspot.com/6817114/diff/10001/debugger/QT/SkDebuggerGUI.c...
debugger/QT/SkDebuggerGUI.cpp:211: fPlayback =
SkNEW_ARGS(SkTimedPicturePlayback,
I thought you were going to make the creation of the playback through a virtual
method so you wouldn't have to dupe the other info in this constructor.

[robertphillips, 2012-11-14 13:35:23]

https://codereview.appspot.com/6817114/diff/10001/debugger/QT/SkDebuggerGUI.cpp
File debugger/QT/SkDebuggerGUI.cpp (right):

https://codereview.appspot.com/6817114/diff/10001/debugger/QT/SkDebuggerGUI.c...
debugger/QT/SkDebuggerGUI.cpp:187: class SkTimedPlaybackPicture : public
SkPicture {
On 2012/11/13 21:41:49, DerekS wrote:
> why not call it SkTimedPicture?  The current form is really similar to the
class
> defined directly above.

Done.

https://codereview.appspot.com/6817114/diff/10001/debugger/QT/SkDebuggerGUI.c...
debugger/QT/SkDebuggerGUI.cpp:211: fPlayback =
SkNEW_ARGS(SkTimedPicturePlayback,
I implemented that but it was more fragile then this solution. SkPicture is very
certain that it just uses a base SkPicturePlayback class. To have it actually
make sense C++-wise I would've needed to add entry points for all of
SkPicturePlayback's constructors. One possible alternative is to add yet another
SkPicture ctor that takes an SkPicturePlayback-derived class.

This (admittedly fragile) approach works here since we know the exact usage of
the SkPicture classes (i.e., no copy ctor calls, etc.)

[DerekS, 2012-11-14 18:23:31]

lgtm.  I'm still think we should continue to think of better ways to do this
than to have the constructor's mimic what is in SkPicture.cpp.  However, we
don't need to hold up progress as we consider this.

[robertphillips, 2012-11-15 14:58:20]

committed as r6430