Add stack-scanning fallback to Stackwalker{AMD64,ARM}.

R=jimb at http://breakpad.appspot.com/206001/show

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@704 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/processor/stackwalker_arm.h

@@ -69,10 +69,19 @@ class StackwalkerARM : public Stackwalker {
 
  private:
   // Implementation of Stackwalker, using arm context and stack conventions.
-  // TODO: currently stubbed out, needs CFI symbol dumper support
   virtual StackFrame* GetContextFrame();
   virtual StackFrame* GetCallerFrame(const CallStack *stack);
 
+  // Use cfi_frame_info (derived from STACK CFI records) to construct
+  // the frame that called frames.back(). The caller takes ownership
+  // of the returned frame. Return NULL on failure.
+  StackFrameARM *GetCallerByCFIFrameInfo(const vector<StackFrame *> &frames,
+                                         CFIFrameInfo *cfi_frame_info);
+
+  // Scan the stack for plausible return addresses. The caller takes ownership
+  // of the returned frame. Return NULL on failure. 
+  StackFrameARM *GetCallerByStackScan(const vector<StackFrame *> &frames);
+
   // Stores the CPU context corresponding to the youngest stack frame, to
   // be returned by GetContextFrame.
   const MDRawContextARM *context_;