Next phase of the move, reformat use C++ features.

Use the libbacktrace C++ interface instead of the C interface in debuggerd.

Reformat the debuggerd code to be closer to Google C++ style.

Fix all debuggerd casts to be C++ casts.

Add a frame number to the frame data structure for ease of formatting and
add another FormatFrameData function.

Change the format_test to use the new FormatFrameData function.

Modify all of the backtrace_test to use the C++ interface.

Change-Id: I10e1610861acf7f4a3ad53276b74971cfbfda464
diff --git a/include/backtrace/backtrace.h b/include/backtrace/backtrace.h
index fa81f21..cfcbf0f 100644
--- a/include/backtrace/backtrace.h
+++ b/include/backtrace/backtrace.h
@@ -44,6 +44,7 @@
 } backtrace_map_info_t;
 
 typedef struct {
+  size_t num;             /* The current fame number. */
   uintptr_t pc;           /* The absolute pc. */
   uintptr_t sp;           /* The top of the stack. */
   size_t stack_size;      /* The size of the stack, zero indicate an unknown stack size. */