scripts/pybootchart: Port to python3

This updates the pybootchart code (used for viewing build timing profiles)
to use python3. The bulk of the changes are to use gi instead of pygtk, i.e.
port from gtk+2 to gtk+3.

The main change is to make the bootchart widget inherit gtk.Scrollable
and change the way the scrollbars are implemented to match the new method
upstream. The drawing code used cairo already so can remain unchanged,

(From OE-Core rev: 949144681ad7f536732169351cab6d0612e9c566)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/pybootchartgui/pybootchartgui/draw.py

@@ -19,6 +19,7 @@ import math
 import re
 import random
 import colorsys
+import functools
 from operator import itemgetter
 
 class RenderOptions:
@@ -449,7 +450,7 @@ def render_charts(ctx, options, clip, trace, curr_y, w, h, sec_w):
                             [(sample.time,
                               # Sum up used space of all volumes including the current one
                               # so that the graphs appear as stacked on top of each other.
-                              reduce(lambda x,y: x+y,
+                              functools.reduce(lambda x,y: x+y,
                                      [sample.records[volume] - min_used[volume]
                                       for volume in volumes[0:i]
                                       if volume in sample.records],
@@ -501,7 +502,7 @@ def render_processes_chart(ctx, options, trace, curr_y, w, h, sec_w):
              TASK_COLOR_SYSROOT, off_x+360, curr_y + 45, leg_s)
     draw_legend_box (ctx, "Package", \
              TASK_COLOR_PACKAGE, off_x+480, curr_y + 45, leg_s)
-    draw_legend_box (ctx, "Package Write",
+    draw_legend_box (ctx, "Package Write", \
              TASK_COLOR_PACKAGE_WRITE, off_x+600, curr_y + 45, leg_s)
 
     ctx.set_font_size(PROC_TEXT_FONT_SIZE)
@@ -518,13 +519,14 @@ def render_processes_chart(ctx, options, trace, curr_y, w, h, sec_w):
                     trace.processes[val][1] - s < options.app_options.mintime:
                 continue
             task = val.split(":")[1]
-            #print val
-            #print trace.processes[val][1]
-            #print s
+            #print(val)
+            #print(trace.processes[val][1])
+            #print(s)
+
             x = chart_rect[0] + (s - offset) * sec_w
             w = ((trace.processes[val][1] - s) * sec_w)
 
-            #print "proc at %s %s %s %s" % (x, y, w, proc_h)
+            #print("proc at %s %s %s %s" % (x, y, w, proc_h))
             col = None
             if task == "do_compile":
                 col = TASK_COLOR_COMPILE