Handle frame pointer omission, (#21), part 4 (final part!): FPO stackwalker.

r=bryner
 - This change allows Airbag to properly walk win32 stacks produced by code
   built with MSVC's frame pointer omission optimization (/Oy).  This
   optimization is enabled at /O1 and /O2.
 - There too many interface and file format changes to list here.

http://groups.google.com/group/airbag-dev/browse_thread/thread/85ce85bfa8457ece


git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@42 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/processor/stackwalker_ppc.h

@@ -64,9 +64,8 @@ class StackwalkerPPC : public Stackwalker {
   // Implementation of Stackwalker, using ppc context (stack pointer in %r1,
   // saved program counter in %srr0) and stack conventions (saved stack
   // pointer at 0(%r1), return address at 8(0(%r1)).
-  virtual bool GetContextFrame(StackFrame *frame);
-  virtual bool GetCallerFrame(StackFrame *frame,
-                              const StackFrames *walked_frames);
+  virtual StackFrame* GetContextFrame();
+  virtual StackFrame* GetCallerFrame(const CallStack *stack);
 
   // Stores the CPU context corresponding to the innermost stack frame to
   // be returned by GetContextFrame.